All 39 QA previous year questions (PYQs) from the IPMAT Indore 2023 past year paper, with answers and full solutions.
Free SolutionsNo Login39 Questions
Q1:ipmat indore 2023QA › Time, Speed & DistanceHardSA · TITA
Vinita drives a car which has four gears. The speed of the car in the fourth gear is five times its speed in the first gear. The car takes twice the time to travel a certain distance in the second gear as compared to the third gear. In a 100 km journey, if Vinita travels equal distances in each of the gears, she takes 585 minutes to complete the journey. Instead, if the distances covered in the first, second, third, and fourth gears are 4 km, 4 km, 32 km, and 60 km, respectively, then the total time taken, in minutes, to complete the journey, will be
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The Setup: We are given relative speed and time constraints across four car gears to complete a uniform distance, which we must use to evaluate the time taken for a mixed-distance journey.
Step 1: Define the speed variables and their relations.
Let the speeds in the four gears be v1,v2,v3, and v4.
We are given v4=5v1.
We are also told the time in the 2nd gear is twice the time in the 3rd gear for a constant distance: v2d=2(v3d)⟹v3=2v2.
Step 2: Express the times for the 100 km uniform journey.
The 100 km journey consists of equal distances in each gear, meaning 25 km per gear.
Let x=v11 and y=v21.
This means v41=5x and v31=2y.
The total time equation is:
25(v11)+25(v21)+25(v31)+25(v41)=58525x+25y+25(2y)+25(5x)=58525x+5x+25y+12.5y=58530x+37.5y=585Step 3: Simplify the baseline equation.
Divide the entire equation by 7.5:
4x+5y=78Step 4: Calculate the time for the newly requested journey.
The new distances are 4 km (1st), 4 km (2nd), 32 km (3rd), and 60 km (4th).
Total Time=4(v11)+4(v21)+32(v31)+60(v41)
Substitute x and y:
Total Time=4x+4y+32(2y)+60(5x)Total Time=4x+4y+16y+12xTotal Time=16x+20y
Factor out a 4:
Total Time=4(4x+5y)Step 5: Substitute the baseline value to find the final time.
Total Time=4(78)=312 minutesFinal Answer: 312
Q2:ipmat indore 2023QA › RemainderEasySA · TITA
The remainder when 1!+2!+3!+...+95! is divided by 15 is
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The Setup: We need to find the remainder when a factorial summation sequence (1!+2!+3!+...+95!) is divided by 15.
Step 1: Analyze the divisibility of factorials by 15.
Since 15=3×5, any factorial n! where n≥5 will strictly contain both 3 and 5 as prime factors.
Therefore, for all n≥5, n!≡0(mod15).
Step 2: Evaluate the terms that are not divisible by 15.
The only terms in the sequence that do not contain 5! as a factor are the first four terms:
1!+2!+3!+4!=1+2+6+24=33Step 3: Calculate the final remainder.
The entire sequence modulo 15 reduces simply to 33(mod15).
33=2×15+3
The remainder is 3.
Final Answer: 3
Let a,b,c,d be positive integers such that a+b+c+d=2023. If a:b=2:5 and c:d=5:2, then the maximum possible value of a+c is
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The Setup: Given a sum equation a+b+c+d=2023 for positive integers and specified ratio pairs, we must maximize the sum a+c.
Step 1: Express the variables using their ratios.
Given a:b=2:5, let a=2x and b=5x for some positive integer x.
Given c:d=5:2, let c=5y and d=2y for some positive integer y.
Step 2: Formulate the sum constraint.
Substitute the variables into the total sum equation:
2x+5x+5y+2y=20237x+7y=2023x+y=289Step 3: Optimize the target function.
We want to maximize a+c, which translates to maximizing 2x+5y.
To maximize the value of 2x+5y given the constraint x+y=289, we must make y (which carries the larger coefficient 5) as large as possible.
Since a,b,c,d are strictly positive integers, the scaling factors x and y must be at least 1.
The maximum valid integer value for y occurs when x is minimized at 1.
1+y=289⟹y=288Step 4: Calculate the maximum value.
Max(a+c)=2(1)+5(288)=2+1440=1442Final Answer: 1442
Q4:ipmat indore 2023QA › Linear EquationsEasySA · TITA
In an election with only two contesting candidates, 15% of the voters did not turn up to vote and 50 voters cast invalid votes. It is known that 44% of all the voters in the voting list voted for the winner. If the winner got 200 votes more than the other candidate, then the number of voters in the voting list is
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The Setup: We are asked to determine the total number of voters on a list given percentage-based turnout and fractional vote shares in a two-candidate election.
Step 1: Define the election parameters.
Let V be the total number of eligible voters on the list.
Voters who didn't turn up = 0.15V.
Total votes cast = 0.85V.
Valid votes cast = 0.85V−50.
Step 2: Represent the candidates' vote shares.
The winner got exactly 44% of *all voters on the voting list* (not just valid votes).
W=0.44V
The other candidate (the loser) received the remaining valid votes:
L=Valid Votes−W=(0.85V−50)−0.44V=0.41V−50Step 3: Apply the winning margin constraint to solve for V.
The winner won by exactly 200 votes.
W−L=2000.44V−(0.41V−50)=2000.03V+50=2000.03V=150V=0.03150=5000Final Answer: 5000
Q5:ipmat indore 2023QA › FunctionsMediumSA · TITA
If f(1)=1 and f(n)=3n−f(n−1) for all integers n>1 , then the value of f(2023) is
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The Setup: A recursive sequence is defined as f(n)=3n−f(n−1) with base case f(1)=1. We must find the value of f(2023).
Step 1: Generate the first few terms to identify a pattern.
f(1)=1f(2)=3(2)−1=5f(3)=3(3)−5=4f(4)=3(4)−4=8f(5)=3(5)−8=7f(6)=3(6)−7=11Step 2: Formulate a generalized relationship.
Let's find the difference between every second term (f(n) and f(n−2)):
f(n)=3n−f(n−1)
Substitute the recursive definition for f(n−1):
f(n)=3n−(3(n−1)−f(n−2))f(n)=3n−3n+3+f(n−2)f(n)=f(n−2)+3
This confirms that the odd-indexed terms and even-indexed terms form independent Arithmetic Progressions, each with a common difference of 3.
Step 3: Evaluate f(2023).
Since 2023 is odd, we use the sequence of odd-indexed terms: 1,4,7,10,…
The generic formula for the odd index sequence f(2k−1) is an AP where the first term is 1 and the difference is 3.
Let n=2023. The number of steps (or the term position in the separated odd sequence) is 2n−1.
Term Index=22023−1=1011f(2023)=Base+(Term Index)×Differencef(2023)=1+1011×3f(2023)=1+3033=3034Final Answer: 3034
Q6:ipmat indore 2023QA › CirclesHardSA · TITA
In the xy-plane let A=(−2,0),B=(2,0) . Define the set S as the collection of all points C on the circle x2+y2=4 such that the area of the triangle ABC is an integer. The number of points in the set S is
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The Setup: Points A=(−2,0) and B=(2,0) lie on the x-axis. We must find all points C on the circle x2+y2=4 such that the area of △ABC is an integer.
Step 1: Define the area of the triangle.
The base of the triangle is the segment AB connecting (−2,0) and (2,0). Its length is exactly 4.
Let point C have coordinates (x,y). The height of the triangle relative to base AB is the absolute value of the y-coordinate, ∣y∣.
Area=21×base×height=21×4×∣y∣=2∣y∣Step 2: Establish integer constraints for the area.
We require the Area (2∣y∣) to be a positive integer k (a valid geometric triangle must have an area strictly greater than 0).
2∣y∣=k⟹∣y∣=2k
Since C lies on the circle x2+y2=4, the maximum possible value for ∣y∣ is the radius, 2.
0<∣y∣≤2⟹0<2k≤2⟹k∈{1,2,3,4}Step 3: Map the valid area states back to coordinate points.
For each valid k, we substitute ∣y∣=k/2 back into the circle equation x2=4−y2 to count the distinct points:
* If k=1: ∣y∣=0.5⟹y=±0.5. x2=4−0.25=3.75. This yields 2 values for x per y, giving 4 points.
* If k=2: ∣y∣=1⟹y=±1. x2=4−1=3. This gives 4 points.
* If k=3: ∣y∣=1.5⟹y=±1.5. x2=4−2.25=1.75. This gives 4 points.
* If k=4: ∣y∣=2⟹y=±2. x2=4−4=0. Here x=0 uniquely, giving exactly 1 point for y=2 and 1 point for y=−2, totaling 2 points.
Step 4: Sum the valid points.
Total Points=4+4+4+2=14Final Answer: 14
If three consecutive coefficients in the expansion of (x+y)n are in the ratio 1:9:63, then the value of n is
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The Setup: We are given three consecutive coefficients in the binomial expansion of (x+y)n strictly in the ratio 1:9:63. We must determine the power n.
Step 1: Express the coefficients algebraically.
Let the three consecutive coefficients be (r−1n), (rn), and (r+1n).
We are given two ratio equations:
(r−1n)(rn)=19=9(rn)(r+1n)=963=7Step 2: Apply the standard binomial coefficient ratio formula.
The ratio (k−1n)(kn) simplifies universally to kn−k+1.
Apply this to our first equation (k=r):
rn−r+1=9⟹n−r+1=9r⟹n=10r−1
Apply this to our second equation (k=r+1):
r+1n−(r+1)+1=7⟹r+1n−r=7⟹n−r=7r+7⟹n=8r+7Step 3: Solve the linear system for r and n.
Equate the two expressions for n:
10r−1=8r+72r=8⟹r=4
Substitute r back into either equation to find n:
n=10(4)−1=39Final Answer: 39
In a chess tournament, there are four groups, each containing an equal number of players. Each player plays
1. against every other player belonging to one's own group exactly once;
2. against each player belonging to one of the remaining three groups exactly twice;
3. against each player belonging to one of the remaining two groups exactly three times; and
4. against each player belonging to the remaining group exactly four times.
If there are more than 1000 matches being played in the tournament, the minimum possible number of players in each group is
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The Setup: A chess tournament consists of four equal groups. Players play matches inside their group and against the other three groups at varying frequencies (1×,2×,3×,4×). We must find the minimum group size to surpass 1000 total matches.
Step 1: Analyze the match distribution logic.
Let each of the 4 groups have k players. Total players = 4k.
Every group must be assigned an inter-group match frequency of 2,3, and 4 against the other three groups.
This is perfectly modeled by weighting the edges of a K4 graph with values {2,3,4} such that every vertex touches exactly one of each weight. Such a configuration requires three distinct perfect matchings on K4, meaning the edge weights between the 6 pairs of groups are exactly: two 2s, two 3s, and two 4s.
Step 2: Calculate total inter-group matches.
Between any two groups of size k playing each other w times, the number of matches is k×k×w=wk2.
Summing over the 6 pairs of groups:
Inter-Group Matches=k2(2+2+3+3+4+4)=18k2Step 3: Calculate total intra-group matches.
Each player plays everyone in their own group exactly once.
For one group, the matches are (2k)=2k(k−1).
Since there are 4 groups:
Intra-Group Matches=4×2k(k−1)=2k(k−1)=2k2−2kStep 4: Formulate the total matches inequality.
Total Matches=18k2+2k2−2k=20k2−2k
We are given that there are more than 1000 matches:
20k2−2k>1000⟹10k2−k>500Step 5: Test integer values for k to find the minimum.
* If k=7: 10(49)−7=490−7=483 (Fails, 483≯500)
* If k=8: 10(64)−8=640−8=632 (Succeeds, 632>500)
The minimum possible number of players in each group is 8.
Final Answer: 8
Q9:ipmat indore 2023QA › LogarithmsEasySA · TITA
The product of the roots of the equation log22(log2x)2−5log2x+6=0 is
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The Setup: We need to find the product of the roots for the logarithmic equation log22(log2x)2−5log2x+6=0.
Step 1: Simplify the first term using logarithm properties.
The term log2(2y) universally simplifies to y.
Thus, log2(2(log2x)2) simplifies directly to (log2x)2.
The equation becomes:
(log2x)2−5log2x+6=0Step 2: Apply a variable substitution.
Let t=log2x. The equation is a standard quadratic:
t2−5t+6=0Step 3: Solve for t and reverse the substitution.
Factor the quadratic:
(t−2)(t−3)=0⟹t=2 or t=3
Reverse the substitution to solve for the roots in terms of x:
If t=2⟹log2x=2⟹x=22=4
If t=3⟹log2x=3⟹x=23=8Step 4: Calculate the product of the roots.
Product=4×8=32Final Answer: 32
The total number of positive integer solutions of 21≤a+b+c≤25 is
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The Setup: We must find the total number of positive integer solutions to the bounded inequality 21≤a+b+c≤25.
Step 1: Normalize the variables to utilize Stars and Bars.
Since a,b,c must be strictly positive integers (≥1), let:
a=x+1b=y+1c=z+1
where x,y,z are non-negative integers (≥0).
Substitute these into the inequality:
21≤(x+1)+(y+1)+(z+1)≤2521≤x+y+z+3≤2518≤x+y+z≤22Step 2: Apply the combinatorics formula for exact sums.
The number of non-negative integer solutions to x+y+z=n is given by (3−1n+3−1)=(2n+2).
We need to sum this over n∈{18,19,20,21,22}:
Solutions=(220)+(221)+(222)+(223)+(224)Step 3: Evaluate the sum.
Calculate each combination (2k)=2k(k−1):
(220)=220×19=190(221)=221×20=210(222)=222×21=231(223)=223×22=253(224)=224×23=276Total=190+210+231+253+276=1160Final Answer: 1160
Q11:ipmat indore 2023QA › ModulusMediumSA · TITA
The length of the line segment joining the two intersection points of the curves y=4970−∣x∣ and y=x2 is
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The Setup: We must find the geometric length of the line segment connecting the two intersection points of the absolute value function y=4970−∣x∣ and the parabola y=x2.
Step 1: Set the equations equal to find intersection points.
x2=4970−∣x∣
Rearrange to form a quadratic in terms of ∣x∣, recognizing that x2=∣x∣2:
∣x∣2+∣x∣−4970=0Step 2: Factor the quadratic equation.
We need two integers that multiply to −4970 and add to 1.
Note that 4970=10×497=10×7×71=70×71.
(∣x∣+71)(∣x∣−70)=0Step 3: Solve for x and locate the coordinates.
Since absolute value ∣x∣ must be non-negative, ∣x∣=−71 is rejected.
∣x∣=70⟹x=70 or x=−70
Because the equations are perfectly symmetric across the y-axis, the segment connecting the two points is perfectly horizontal.
Step 4: Calculate the distance.
The length of a horizontal line segment is simply the absolute difference between the x-coordinates.
Length=∣70−(−70)∣=140Final Answer: 140
If f(n)=1+2+3+⋯+(n+1) and g(n)=∑k=1k=nf(k)1, then the least value of n for which g(n) exceeds the value 10099 is:
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The Setup: Given an arithmetic sum base function f(n), we have a reciprocal series g(n). We must find the least integer n that pushes g(n) above the threshold of 99/100.
Step 1: Simplify the base function f(n).
The function is the sum of consecutive integers:
f(n)=1+2+3+⋯+(n+1)=2(n+1)(n+2)Step 2: Construct the series g(n) and apply partial fractions.
g(n)=k=1∑nf(k)1=k=1∑n(k+1)(k+2)2
Split the fraction using partial fraction decomposition:
(k+1)(k+2)2=2(k+11−k+21)Step 3: Evaluate the telescoping sum.
When summing from k=1 to n, all intermediate terms cancel out:
g(n)=2[(21−31)+(31−41)+⋯+(n+11−n+21)]g(n)=2(21−n+21)=1−n+22Step 4: Apply the threshold inequality.
We need g(n)>10099:
1−n+22>0.990.01>n+221001>n+22⟹n+2>200⟹n>198
Since n must be an integer, the least value fulfilling this is 199.
Final Answer: 199
Q13:ipmat indore 2023QA › RemainderEasySA · TITA
The polynomial 4x10−x9+3x11−5x7+cx6+2x5−x4+x3−4x2+6x−2 when divided by x−1 leaves a remainder 2. Then the value of c+6 is
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The Setup: A polynomial divided by (x−1) leaves a remainder of 2. We apply the Polynomial Remainder Theorem to find a missing coefficient c and then compute c+6.
Step 1: Apply the Remainder Theorem.
If a polynomial P(x) is divided by (x−a), the remainder is exactly P(a).
Here, dividing by (x−1) gives a remainder of 2, meaning P(1)=2.
Step 2: Evaluate P(1) algebraically.
Substitute x=1 into the polynomial. For x=1, all powers of x resolve to 1, leaving just the sum of the coefficients.
P(1)=4(1)−1(1)+3(1)−5(1)+c(1)+2(1)−1(1)+1(1)−4(1)+6(1)−2
Group the numerical terms:
P(1)=4−1+3−5+2−1+1−4+6−2+cP(1)=3+cStep 3: Equate to the remainder and solve.
c+3=2⟹c=−1Step 4: Calculate the final expression.
We need the value of c+6.
−1+6=5Final Answer: 5
Assume it is the beginning of the year today. Ankita will earn INR 10,000 at the end of the year, which she plans to invest in a bank deposit immediately at a fixed simple interest of 0.5% per annum. Her yearly income will increase by INR 10,000 every year, and the fixed simple interest offered by the bank on new deposits will also increase by 0.5% per annum every year. If Ankita continues to invest all her yearly income in new bank deposits at the end of each year, the total interest earned by her, in INR, in five years from today will be
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The Setup: We evaluate sequential deposits placed at the end of each year with growing principals and scaling simple interest rates over a bounded 5-year timeline from 'today' (Start of Year 1).
Step 1: Chart the timeline and investment parameters.
Five years from today implies the timeline ends exactly at the conclusion of Year 5 (T=5).
Simple Interest Formula: Interest=P×R×T.
* Deposit 1 (End of Yr 1, T=1): Earns 10,000. Rate = 0.5%=0.005. Time invested = 4 years (T=1 to T=5).
* Deposit 2 (End of Yr 2, T=2): Income rises by 10k, so earns 20,000. Rate rises by 0.5%, so = 1.0%=0.01. Time invested = 3 years.
* Deposit 3 (End of Yr 3, T=3): Earns 30,000. Rate = 1.5%=0.015. Time invested = 2 years.
* Deposit 4 (End of Yr 4, T=4): Earns 40,000. Rate = 2.0%=0.02. Time invested = 1 year.
* Deposit 5 (End of Yr 5, T=5): Earns 50,000. Rate = 2.5%=0.025. Time invested = 0 years (cashed exactly as deposited).
Step 2: Calculate interest for each independent deposit.
* Interest 1: 10000×0.005×4=200
* Interest 2: 20000×0.010×3=600
* Interest 3: 30000×0.015×2=900
* Interest 4: 40000×0.020×1=800
* Interest 5: 50000×0.025×0=0Step 3: Sum the total interest.
Total Interest=200+600+900+800+0=2500Final Answer: 2500
Q15:ipmat indore 2023QA › Time & WorkMediumSA · TITA
Amisha can complete a particular task in twenty days. After working for four days she fell sick for four days and resumed the work on the ninth day but with half of her original work rate. She completed the task in another twelve days with the help of a co-worker who joined her from the ninth day. The number of days required for the co-worker to complete the task alone would be
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The Setup: A worker finishes a partial task at shifting rates and enlists a co-worker to complete the remaining fraction. By mapping their combined work capacity against the remaining work, we can isolate the co-worker's individual rate.
Step 1: Establish Amisha's work rates.
Amisha's standard rate allows her to finish in 20 days, so her normal rate is A=201 tasks/day.
When she resumes, she works at half her original rate, making her new rate A′=401 tasks/day.
Step 2: Calculate work completed before the break.
Amisha works normally for 4 days.
Work Done=4×(201)=204=51Remaining Work=1−51=54Step 3: Formulate the combined work phase.
She is sick for 4 days, so Day 9 begins the new phase. From Day 9, she and her co-worker work together for 12 days to finish the job.
Let the co-worker's rate be C tasks/day.
Combined Rate=A′+C=401+CWork done together=12×(401+C)
Set this equal to the remaining work:
12(401+C)=54Step 4: Solve for C and convert to days.
Divide both sides by 12:
401+C=604=151C=151−401
Find a common denominator (120):
C=1208−1203=1205=241
Since the co-worker's rate is 241 of the task per day, it would take them exactly 24 days to complete the task alone.
Final Answer: 24
Q16:ipmat indore 2023QA › Unit DigitEasyMCQ · MCQ
Let p be a positive integer such that the unit digit of p3 is 4. What are the possible unit digits of (p+3)3
A3
B1, 7, 9
C4, 7
D1, 3, 7
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The Setup: We are given a positive integer p such that the unit digit of p3 is exactly 4. We need to determine the possible unit digits of the expression (p+3)3.
Step 1: Determine the unit digit of p.
We evaluate the cubes of all base digits from 0 to 9 to see which produces a unit digit of 4:
03=0,13=1,23=8,33=27,43=64,53=125,63=216,73=343,83=512,93=729.
The only digit whose cube ends in 4 is 4 itself.
Therefore, the unit digit of p must be 4.
Step 2: Calculate the unit digit of (p+3)3.
Since p≡4(mod10), we substitute this into the target expression:
p+3≡4+3≡7(mod10)
Now, cube this resulting unit digit:
73=343
The unit digit of 343 is 3. Thus, the only possible unit digit for (p+3)3 is 3.
Final Answer: 3
Q17:ipmat indore 2023QA › Integral SolutionsMediumMCQ · MCQ
Let [x] denote the greatest integer not exceeding x and {x} =x−[x] If n is a natural number, then the sum of all values of x satisfying the equation 2[x]=x+n{x} is
A2n(n+2)
B23
C2n(n+1)
Dn
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The Setup: We are given the equation 2[x]=x+n{x}, where n is a natural number, [x] is the greatest integer function, and {x} is the fractional part. We must find the sum of all values of x that satisfy this equation.
Step 1: Express x in terms of its integer and fractional parts.
By definition, any real number x can be written as x=[x]+{x}.
Substitute this into the given equation:
2[x]=([x]+{x})+n{x}[x]=(n+1){x}Step 2: Isolate the fractional part and apply its bounds.
{x}=n+1[x]
By the definition of the fractional part function, 0≤{x}<1.
0≤n+1[x]<1
Since n is a natural number (n≥1), n+1 is strictly positive. Multiply the inequality by n+1:
0≤[x]<n+1
Because [x] must be an integer, the possible values for [x] are the integers 0,1,2,…,n.
Step 3: Formulate x and calculate the sum.
Substitute the expression for {x} back into x=[x]+{x}:
x=[x]+n+1[x]=[x](1+n+11)=[x](n+1n+2)
To find the sum of all valid x, we sum this expression over all possible values of [x] from 0 to n:
Sum=k=0∑nk(n+1n+2)=(n+1n+2)k=0∑nk
Using the sum of the first n integers formula ∑k=0nk=2n(n+1):
Sum=(n+1n+2)(2n(n+1))=2n(n+2)Final Answer:2n(n+2)
The set of all real values of x satisfying the inequality (x−1)(2x+1)3x2(x+1)>0 is
A(−∞,−1) U (−21,0) U (1,+∞)
B(−1,−21) U (1,+∞)
C(−1,0) U (1,+∞)
D(−1,−21) U (0,+∞)
Pick an option to attempt
The Setup: We must find the set of all real values of x that satisfy the rational inequality (x−1)(2x+1)3x2(x+1)>0.
Step 1: Identify the critical points.
Set the numerator and denominator factors to zero to find the critical points where the expression changes sign or becomes undefined:
Numerator: x=0 (multiplicity 2, even), x=−1 (multiplicity 1, odd).
Denominator: x=1 (multiplicity 1, odd), x=−1/2 (multiplicity 3, odd).
The critical points in ascending order are: −1,−1/2,0,1.
Step 2: Evaluate the sign intervals using a test-point method.
Because the factor x2 is always non-negative and touches 0 at x=0, the sign does not change across x=0. We test the regions partitioned by the odd-multiplicity critical points (−1,−1/2,1):
* **Region x>1:** Test x=2. Expression is (+)(+)/(+)(+)>0. (Valid)
* **Region −1/2<x<1 (excluding 0):** Since sign alternates at x=1, this region is negative. (Invalid)
* **Region −1<x<−1/2:** Since sign alternates at x=−1/2, this region is positive. (Valid)
* **Region x<−1:** Since sign alternates at x=−1, this region is negative. (Invalid)
Step 3: Combine the valid intervals.
The strict inequality requires the expression to be strictly greater than 0, so the critical points themselves are not included.
The valid intervals are (−1,−1/2) and (1,+∞).
Set=(−1,−21)∪(1,+∞)Final Answer:(−1,−21)∪(1,+∞)
A goldsmith bought a large solid golden ball at INR 1,000,000 and melted it to make a certain number of solid spherical beads such that the radius of each bead was one-fifth of the radius of the original ball. Assume that the cost of making golden beads is negligible. If the goldsmith sold all the beads at 20% discount on the listed price and made a total profit of 20%, then the listed price or each golden bead, in INR, was
A48000
B12000
C9600
D24000
Pick an option to attempt
The Setup: A solid golden ball costing INR 1,000,000 is melted into smaller spherical beads. The radius of each bead is one-fifth of the original ball's radius. The beads are sold at a 20% discount for a total overall profit of 20%. We must find the listed price per bead.
Step 1: Calculate the number of beads produced.
Let the radius of the original ball be R and the radius of a bead be r. We are given r=5R.
The volume of a sphere is proportional to the cube of its radius.
Number of beads=Volume of one beadVolume of original ball=34πr334πR3=(rR)3=(5)3=125
So, 125 identical beads are produced.
Step 2: Calculate the required revenue per bead.
The total cost is INR 1,000,000.
The total profit made is 20%, so the total revenue generated is 120% of the cost:
Total Revenue=1,000,000×1.20=1,200,000
Since this revenue comes from selling 125 beads, the selling price (SP) per bead is:
SP=1251,200,000=9600Step 3: Calculate the listed price.
The selling price is derived after a 20% discount is applied to the listed price (L).
0.80×L=9600L=0.809600=12000Final Answer: 12000
Q20:ipmat indore 2023QA › CirclesMediumMCQ · MCQ
Which of the following straight lines are both tangent to the circle x2+y2−6x+4y−12=0?
A4x+3y+19=0,4x+3y−31=0
B4x+3y−19=0,4x+3y+31=0
C4x+3y−19=0,4x+3y−31=0
D4x+3y+19=0,4x+3y+31=0
Pick an option to attempt
The Setup: We are asked to identify which pair of straight lines are both tangents to the circle defined by x2+y2−6x+4y−12=0.
Step 1: Determine the center and radius of the circle.
Complete the square for both x and y to convert the equation into standard circle form (x−h)2+(y−k)2=r2:
(x2−6x+9)+(y2+4y+4)=12+9+4(x−3)2+(y+2)2=25
The center of the circle is C=(3,−2) and the radius is r=25=5.
Step 2: Apply the tangent distance formula.
For a line Ax+By+C=0 to be tangent to a circle, the perpendicular distance from the circle's center to the line must exactly equal the radius r.
Looking at the options, all candidate lines have the form 4x+3y+c=0.
Set the perpendicular distance from (3,−2) to the line equal to 5:
42+32∣4(3)+3(−2)+c∣=525∣12−6+c∣=55∣6+c∣=5∣6+c∣=25Step 3: Solve for the constant c.
This absolute value equation yields two valid cases for c:
Case 1: 6+c=25⟹c=19
Case 2: 6+c=−25⟹c=−31
The two tangent lines are 4x+3y+19=0 and 4x+3y−31=0.
Final Answer:4x+3y+19=0,4x+3y−31=0
If A=[132a] where a is a real number and det (A3−3A2−5A)=0 then one of the values of a can be
A4
B6
C1
D5
Pick an option to attempt
The Setup: We are given a 2×2 matrix A with a variable a. We must find a valid value for a given that det(A3−3A2−5A)=0.
Step 1: Factor the matrix polynomial.
A3−3A2−5A=A(A2−3A−5I)
Using the determinant product rule det(XY)=det(X)det(Y), the condition becomes:
det(A)⋅det(A2−3A−5I)=0
This means that either det(A)=0 or det(A2−3A−5I)=0.
Step 2: Test the first determinant condition.
Calculate the determinant of matrix A:
A=[132a]det(A)=(1)(a)−(2)(3)=a−6
If det(A)=0, then a−6=0⟹a=6.
Checking the multiple-choice options provided in the prompt, 6 is a listed option.
Final Answer: 6
Q22:ipmat indore 2023QA › Time, Speed & DistanceEasyMCQ · MCQ
A helicopter flies along the sides of a square field of side length 100 kms. The first side is covered at a speed of 100 kmph, and for each subsequent side the speed is increased by 100 kmph till it covers all the sides. The average speed of the helicopter is
A250 kmph
B184 kmph
C192 kmph
D200 kmph
Pick an option to attempt
The Setup: A helicopter flies around the perimeter of a 100 km×100 km square field. Its speed starts at 100 kmph for the first side and increases by 100 kmph for each subsequent side. We must calculate its average speed for the entire trip.
Step 1: Determine the distance and speed for each leg.
Since the field is a square with side length 100 km, the helicopter flies four distinct legs of 100 km each.
* Side 1: Distance = 100 km, Speed = 100 kmph
* Side 2: Distance = 100 km, Speed = 200 kmph
* Side 3: Distance = 100 km, Speed = 300 kmph
* Side 4: Distance = 100 km, Speed = 400 kmphStep 2: Calculate the time taken for each leg.
Using Time = Distance / Speed:
* T1=100100=1 hour
* T2=200100=21 hour
* T3=300100=31 hour
* T4=400100=41 hourStep 3: Calculate the average speed.
Average Speed=Total TimeTotal DistanceTotal Distance=4×100=400 kmTotal Time=1+21+31+41=1212+6+4+3=1225 hoursAverage Speed=1225400=400×2512=16×12=192 kmphFinal Answer: 192 kmph
(b+c)(a+b)=(d+a)(c+d) which of the following statements is always true?
Aa+b+c+d=0
Ba=c, or a+b+c+d=0
Ca=c
Da=c, and b=d
Pick an option to attempt
The Setup: We are given the algebraic equality b+ca+b=d+ac+d. We need to evaluate which conditional statement must necessarily follow.
Step 1: Cross-multiply to clear the fractions.
(a+b)(a+d)=(c+d)(b+c)Step 2: Expand both sides of the equation.
a2+ad+ab+bd=bc+c2+bd+cdStep 3: Simplify and factor the expression.
Subtract the right side from the left side. Notice that the +bd term exists on both sides and cancels out:
a2+ad+ab−bc−c2−cd=0
Group the terms strategically to factor by grouping. Pair the squares, and group the remaining terms by common factors b and d:
(a2−c2)+b(a−c)+d(a−c)=0
Apply the difference of squares identity to the first term:
(a−c)(a+c)+b(a−c)+d(a−c)=0
Factor out the common binomial term (a−c):
(a−c)(a+c+b+d)=0Step 4: Evaluate the Zero Product Property.
For this product to be zero, at least one of the factors must be zero:
Factor 1: a−c=0⟹a=c
Factor 2: a+b+c+d=0
Thus, it must always be true that a=c or a+b+c+d=0.
Final Answer:a=c, or a+b+c+d=0
If the harmonic mean of the roots of the equation (5+2)x2−bx+8+25=0 is 4 then the value of b is
A2
B4−5
C3
D4+5
Pick an option to attempt
The Setup: We are given a quadratic equation (5+2)x2−bx+8+25=0 whose roots have a harmonic mean of 4. We must find the value of b.
Step 1: Establish the Harmonic Mean formula for the roots.
Let the roots of the quadratic equation be α and β.
The Harmonic Mean (HM) of two numbers is defined as:
HM=α+β2αβ
We are given that HM=4.
Step 2: Extract the sum and product of the roots from the quadratic.
Using Vieta's formulas for Ax2+Bx+C=0:
Sum of roots (α+β)=−AB=5+2bProduct of roots (αβ)=AC=5+28+25Step 3: Substitute Vieta's results into the Harmonic Mean equation.
4=(5+2b)2(5+28+25)
Notice that the complex denominator (5+2) neatly cancels out from both the numerator and the denominator of the large fraction:
4=b2(8+25)4=b16+45Step 4: Solve for b.
4b=16+45
Divide both sides by 4:
b=4+5Final Answer:4+5
If the difference between compound interest and simple interest for a certain amount of money invested for 3 years at an annual interest rate of 10% is INR 527, then the amount invested in INR is
A17000
B15000
C1500
D170000
Pick an option to attempt
The Setup: The difference between Compound Interest (CI) and Simple Interest (SI) on a principal amount invested for 3 years at a 10% annual rate is INR 527. We need to determine the original principal amount.
Step 1: State the 3-year CI and SI difference formula.
For a principal P invested for exactly 3 years at an annual interest rate R (expressed as a percentage), the difference D between CI and SI is given by the standard derived formula:
D=P(100R)2(100R+3)Step 2: Substitute the known values into the formula.
We are given D=527 and R=10.
527=P(10010)2(10010+3)527=P(0.1)2(0.1+3)527=P(0.01)(3.1)527=0.031PStep 3: Solve for the Principal P.
P=0.031527=31527,000
Divide 527 by 31 to simplify the fraction:
527÷31=17P=17,000Final Answer: 17000
Let a1,a2,a3 be three distinct real numbers in geometric progression. If the equations a1x2+2a2x+a3=0 and b1x2+2b2x+b3=0 have a common root, then which of the following is necessarily true?
Aa1b1,a2b2,a3b3 are in geometric progression
Bb1,b2,b3 are in geometric progression
Cb1,b2,b3 are in arithmetic progression
Da1b1,a2b2,a3b3 are in arithmetic progression
Pick an option to attempt
The Setup: Given three distinct real numbers a1,a2,a3 in a geometric progression (GP), we are told the quadratics a1x2+2a2x+a3=0 and b1x2+2b2x+b3=0 share a common root. We must deduce the relationship between the ratios of their coefficients.
Step 1: Analyze the first quadratic equation.
Since a1,a2,a3 are in GP, they satisfy the property a22=a1a3.
Check the discriminant (D) of the first quadratic equation a1x2+2a2x+a3=0:
D=(2a2)2−4(a1)(a3)=4a22−4a1a3
Substitute a1a3 for a22:
D=4(a1a3)−4a1a3=0
Since D=0, the first equation has a single repeated real root. We find this root using the quadratic formula:
x=2a1−2a2=−a1a2Step 2: Apply the common root constraint.
Because the two equations share a common root, and the first equation only has *one* unique root, this root (x=−a2/a1) must exactly be the root of the second equation b1x2+2b2x+b3=0.
Substitute x=−a2/a1 into the second equation:
b1(−a1a2)2+2b2(−a1a2)+b3=0b1a12a22−2b2a1a2+b3=0Step 3: Simplify the relationship to match the options.
Divide the entire equation by a3:
b1a12a3a22−2b2a1a3a2+a3b3=0
Use the GP identity a22=a1a3 to simplify the denominators.
For the first term: a12a3a22=a12a3a1a3=a11
For the second term: a1a3a2=a22a2=a21
Substitute these back:
a1b1−2a2b2+a3b3=02(a2b2)=a1b1+a3b3
This fits the exact definition of an Arithmetic Progression (AP) where the middle term is the arithmetic mean of the outer terms.
Final Answer:a1b1.a2b2,a3b3 are in arithmetic progression
Q27:ipmat indore 2023QA › TrianglesHardMCQ · MCQ
In a triangle ABC, let D be the midpoint of BC, and AM be the altitude on BC. If the lengths of AB, BC and CA are in the ratio of 2:4:3, then the ratio of the lengths of BM and AD would be
A11:410
B12:11
C11:12
D410:11
Pick an option to attempt
The Setup: In △ABC, D is the midpoint of BC, and AM is the altitude on BC. With side ratios AB:BC:CA=2:4:3, we must find the length ratio BM:AD.
Step 1: Assign algebraic lengths to the sides.
Let the sides be c=AB=2x, a=BC=4x, and b=CA=3x.
Since D is the midpoint of BC, BD=2BC=2x.
Step 2: Calculate the length of BM.
Use the Law of Cosines to find cosB in △ABC:
cosB=2aca2+c2−b2=2(4x)(2x)(4x)2+(2x)2−(3x)2cosB=16x216x2+4x2−9x2=16x211x2=1611
In the right-angled △ABM, the segment BM represents the adjacent side to angle B. Thus, BM=c⋅cosB:
BM=2x(1611)=811xStep 3: Calculate the length of the median AD.
Apply Apollonius's Theorem to the median AD:
AB2+AC2=2(AD2+BD2)(2x)2+(3x)2=2(AD2+(2x)2)4x2+9x2=2AD2+8x213x2−8x2=2AD25x2=2AD2⟹AD2=25x2⟹AD=2x5=2x10Step 4: Compute the ratio BM:AD.
Ratio=2x10811x=811×102=81022=41011Final Answer:11:410
Let a,b,c be real numbers greater than 1, and n be a positive real number not equal to 1. If logn(log2a)=1;logn(log2b)=2 and logn(log2c)=3 then which of the following is true?
A(b−a)n=(c−b)
Ban+bn=cn
Ca+b=c
D(an+b)n=ac
Pick an option to attempt
The Setup: We are given a system of nested logarithms: logn(log2a)=1, logn(log2b)=2, and logn(log2c)=3. We must establish which given algebraic relationship holds true.
Step 1: Convert the logarithmic equations into exponential form.
Using the rule logx(y)=z⟹y=xz:
Equation 1: log2a=n1=n⟹a=2n
Equation 2: log2b=n2⟹b=2n2
Equation 3: log2c=n3⟹c=2n3Step 2: Express variables in terms of each other.
Notice that the exponent of b is the square of the exponent of a:
b=2n2=(2n)n=an
Notice that the exponent of c relates to b:
c=2n3=(2n2)n=bn
We also know that c relates to a by c=(2n)n2=an2.
Additionally, multiply a and c:
ac=2n⋅2n3=2n+n3
Alternatively, ac=a⋅bn.
Step 3: Evaluate the multiple-choice options.
We test the specific option (an+b)n=ac to see if it holds true.
Substitute b=an into the left side:
Left Side=(b+b)n=(2b)n
Distribute the exponent:
(2b)n=2n⋅bn
Now, substitute our initial mappings back in. We know 2n=a and bn=c:
2n⋅bn=a⋅c
The left side mathematically perfectly matches the right side ac.
Final Answer:(an+b)n=ac
Consider an 8×8 chessboard. The number of ways 8 rooks can be placed on the board such that no two rooks are in the same row and no two are in the same column is
A7
B7!
C8
D8!
Pick an option to attempt
The Setup: We need to find the total number of ways to place 8 indistinguishable rooks on a standard 8×8 chessboard such that no two rooks threaten each other (no two share the same row or column).
Step 1: Place the rooks sequentially row by row.
To ensure no two rooks share a row, exactly one rook must be placed in each of the 8 rows.
* Row 1: The first rook can be placed in any of the 8 squares (columns) in the first row.
* Row 2: The second rook must be placed in the second row, but it cannot share the column occupied by the first rook. This leaves 7 valid squares.
* Row 3: The third rook cannot share a column with the first two rooks, leaving 6 valid squares.
* …
* Row 8: The final rook is forced into the single remaining unoccupied column.
Step 2: Calculate total configurations.
The total number of valid placements is the product of the independent choices for each row:
Total Ways=8×7×6×5×4×3×2×1=8!Final Answer: 8!
The Setup: We are given the conic equation x2+y2−2x−4y+5=0 and asked to classify the specific geometric shape it represents.
Step 1: Reformat the equation using completing the square.
Group the x terms and y terms:
(x2−2x)+(y2−4y)=−5
Complete the square for x by adding (−2/2)2=1:
Complete the square for y by adding (−4/2)2=4:
Balance the equation by adding these to the right side as well:
(x2−2x+1)+(y2−4y+4)=−5+1+4Step 2: Simplify and classify the equation.
(x−1)2+(y−2)2=0
This is the standard form of a circle (x−h)2+(y−k)2=r2.
Here, the radius squared is exactly 0 (r=0).
A circle with a radius of 0 mathematically collapses into a single coordinate point located at its center, (1,2).
Final Answer: a point
A person standing at the centre of an open ground first walks 32 meters towards the east, takes a right turn and walks 16 meters, takes another right turn and walks 8 meters, and so on. How far will the person be from the original starting point after an infinite number of such walks in this pattern?
A32 meters
B532 meters
C64 meters
D564 meters
Pick an option to attempt
The Setup: A person maps out a path taking consecutive 90∘ right turns, with each leg of the journey halving in distance (32m,16m,8m…). We must find their net displacement from the origin after infinite turns.
Step 1: Establish a coordinate system.
Let the starting point be the origin (0,0).
* Leg 1: 32m East (Positive x-direction).
* Leg 2: 16m South (Negative y-direction).
* Leg 3: 8m West (Negative x-direction).
* Leg 4: 4m North (Positive y-direction).
* Leg 5: 2m East (Positive x-direction).
This pattern continues infinitely.
Step 2: Calculate the net displacement on the x-axis.
The x-coordinate sequence alternates direction every two steps: 32 (East), −8 (West), 2 (East), −0.5 (West) …
This forms an infinite geometric progression where the first term a=32 and the common ratio r=−41.
Xfinal=1−ra=1−(−1/4)32=5/432=32×54=5128Step 3: Calculate the net displacement on the y-axis.
The y-coordinate sequence begins on the second step: −16 (South), 4 (North), −1 (South) …
This forms an infinite geometric progression where a=−16 and r=−41. (We'll use magnitude for distance).
Yfinal=1−(−1/4)16=5/416=16×54=564Step 4: Calculate the final straight-line distance.
Use the Pythagorean theorem: D=Xfinal2+Yfinal2.
D=(5128)2+(564)2=56422+12=5645
Simplify by converting the denominator:
D=(5⋅5)645=564Final Answer:564 meters
Q32:ipmat indore 2023QA › LogarithmsHardMCQ · MCQ
If log(cosx)(sinx)+log(sinx)(cosx)=2, then the value of x is
Anπ+4π,n is an integer
B2nπ+4π,n is an integer
C4nπ,n is an integer
D4nπ+4π,n is an integer
Pick an option to attempt
The Setup: We must solve for x given the trigonometric logarithmic equation logcosx(sinx)+logsinx(cosx)=2.
Step 1: Use substitution to solve the algebra.
By the base-change inversion property of logarithms, logab=logba1.
Let t=logcosx(sinx). The equation becomes:
t+t1=2
Multiply by t to form a quadratic:
t2−2t+1=0⟹(t−1)2=0⟹t=1Step 2: Re-substitute to find the trigonometric relation.
logcosx(sinx)=1⟹cos1x=sinx⟹sinx=cosx
Dividing by cosx yields tanx=1.
Step 3: Evaluate the domain restrictions for logarithms.
For a logarithm logba to be defined, the base b>0,b=1, and the argument a>0.
Thus, we strictly require sinx>0, sinx=1, cosx>0, and cosx=1.
This strictly restricts valid solutions for x exclusively to the first quadrant of the unit circle.
Step 4: Find the general solution for x.
The first-quadrant angle where tanx=1 is 4π.
To represent all coterminal first-quadrant angles, we add full 360∘ rotations, which is 2nπ, where n is an integer.
x=2nπ+4πFinal Answer:2nπ+4π, n is an integer
A rabbit is sitting at the base of a staircase which has 10 steps. It proceeds to the top of the staircase by climbing either one step at a time or two steps at a time. The number of ways it can reach the top is
A144
B89
C34
D55
Pick an option to attempt
The Setup: A rabbit climbs a 10-step staircase, taking either one or two steps at a time. We must find the total number of unique ways to reach the top.
Step 1: Establish the recursive relationship.
Let Wn be the number of ways to reach the n-th step.
To reach step n, the rabbit must have either taken a single step from step n−1, or a double step from step n−2.
Therefore, the total ways to reach step n is the sum of the ways to reach the previous two steps: Wn=Wn−1+Wn−2.
This forms the Fibonacci sequence.
Step 2: Define the base cases.
* To reach Step 1 (W1): Exactly 1 way (one 1-step).
* To reach Step 2 (W2): Exactly 2 ways (two 1-steps, or one 2-step).
Step 3: Compute the sequence up to step 10.
* W3=W2+W1=2+1=3
* W4=3+2=5
* W5=5+3=8
* W6=8+5=13
* W7=13+8=21
* W8=21+13=34
* W9=34+21=55
* W10=55+34=89Final Answer: 89
The probability that a randomly chosen positive divisor of 102023 is an integer multiple of 102001 is
A202322
B20242232
C202422
D20232222
Pick an option to attempt
The Setup: We are asked for the probability that a randomly chosen positive divisor of 102023 is also an integer multiple of 102001.
Step 1: Determine the total number of divisors (the sample space).
First, find the prime factorization of the base number:
102023=(2×5)2023=22023×52023
The formula for the total number of divisors of pa⋅qb is (a+1)(b+1).
Total Divisors=(2023+1)(2023+1)=20242Step 2: Determine the number of valid target divisors.
A divisor D is a multiple of 102001 (which is 22001×52001) if its prime factorization D=2x×5y meets the constraints:
* For base 2: 2001≤x≤2023
* For base 5: 2001≤y≤2023
Calculate the number of integer choices for the exponents x and y:
Choices for x=2023−2001+1=23.
Choices for y=2023−2001+1=23.
Number of valid multiples=23×23=232Step 3: Calculate the probability.
Probability=Total DivisorsValid Multiples=20242232Final Answer:20242232
Q35:ipmat indore 2023QA › Set TheoryEasyMCQ · MCQ
In a group of 120 students, 80 students are from the Science stream and the rest are from the Commerce stream. It is known that 70 students support Mumbai Indians in the Indian Premier League; all the other students support Chennai Super Kings. The number of Science students who are supporters of Mumbai Indians is
AExactly 20
BBetween 15 and 25
C30 or more
DBetween 20 and 25
Pick an option to attempt
The Setup: A group of 120 students comprises 80 Science and 40 Commerce students. Exactly 70 students support Mumbai Indians (MI), while the rest support Chennai Super Kings (CSK). We must establish the possible range of Science students supporting MI.
Step 1: Establish the basic parameters.
Total Students = 120
Science Students = 80
Commerce Students = 120−80=40
Total MI Supporters = 70Step 2: Calculate the maximum bound for Science MI supporters.
Let x be the number of Science students who support MI.
The maximum possible value for x occurs if as many MI supporters as possible are drawn from the Science pool.
Since there are only 70 MI supporters total, and 80 Science students exist, it is mathematically possible for all 70 MI supporters to be Science students.
Max(x)=70Step 3: Calculate the minimum bound for Science MI supporters.
The minimum possible value for x occurs if as many MI supporters as possible are drawn from the Commerce pool.
There are only 40 Commerce students. If all 40 of them support MI, the remaining MI supporters must be Science students.
Min(x)=70(Total MI)−40(Commerce MI)=30Step 4: Conclude the range.
The number of Science students supporting MI must sit exactly in the inclusive range 30≤x≤70.
Looking at the options, the constraint '30 or more' is the only logically correct bounding descriptor.
Final Answer: 30 or more
If a three-digit number is chosen at random, what is the probability that it is divisible neither by 3 nor by 4?
A41
B21
C32
D31
Pick an option to attempt
The Setup: We are asked for the probability that a randomly chosen 3-digit number is divisible by *neither* 3 nor 4.
Step 1: Calculate the size of the sample space.
The 3-digit numbers run inclusively from 100 to 999.
Total 3-digit numbers=999−100+1=900Step 2: Use the Inclusion-Exclusion principle to find the complement.
We first find the number of integers divisible by 3 OR 4: ∣A∪B∣=∣A∣+∣B∣−∣A∩B∣.
* Divisible by 3: The sequence is 102,105…999.
Count=3999−102+1=297/3+1=300
* Divisible by 4: The sequence is 100,104…996.
Count=4996−100+1=896/4+1=225
* Divisible by 12 (Intersection): The sequence is 108,120…996.
Count=12996−108+1=888/12+1=75Divisible by 3 or 4=300+225−75=450Step 3: Calculate the target probability.
The target numbers are those *not* divisible by 3 or 4.
Target count=Total−(Divisible by 3 or 4)=900−450=450Probability=900450=21Final Answer:21
The minimum number of times a fair coin must be tossed so that the probability of getting at least one head exceeds 0.8 is
A5
B6
C3
D7
Pick an option to attempt
The Setup: We must find the minimum number of independent coin tosses required for the probability of getting at least one head to exceed 0.8.
Step 1: Formulate the probability equation.
The probability of getting *at least one* head is the complement of getting *zero* heads (all tails).
P(at least 1 H)=1−P(all T)
For a fair coin tossed n times, the probability of getting all tails is (21)n.
P(at least 1 H)=1−(21)nStep 2: Set up and solve the inequality.
We require this probability to strictly exceed 0.8.
1−(21)n>0.81−0.8>(21)n0.2>(21)n
Convert the decimal to a fraction (0.2=51):
51>2n1
Inverting the fractions flips the inequality:
2n>5Step 3: Test integer values for n.
* If n=1: 21=2≯5
* If n=2: 22=4≯5
* If n=3: 23=8>5 (Valid)
The minimum integer number of tosses required is 3.
Final Answer: 3
If cosα + cosβ = 1 then the maximum value of sinα−sinβ is
A2
B2
C3
D1
Pick an option to attempt
The Setup: Given the constraint cosα+cosβ=1, we must find the maximum value of sinα−sinβ.
Step 1: Rewrite both expressions with the sum-to-product identities.
Let u=2α+β and v=2α−β. The constraint and the target expression become:
cosα+cosβ=2cosucosv=1sinα−sinβ=2cosusinv
Both share the same factor 2cosu, which is what makes the constraint substitutable.
Step 2: Eliminate u using the constraint.
The constraint gives 2cosu=cosv1 directly (note cosv=0). Substitute this into the target:
sinα−sinβ=(cosv1)sinv=tanv
The whole problem has collapsed to maximising tanv.
Step 3: Find the admissible range of v.
cosu is a cosine, so it is bounded by ∣cosu∣≤1:
2cosv1≤1⟹∣cosv∣≥21
On the branch where tanv is positive and increasing, this restricts v to 0≤v≤3π.
Step 4: Maximise on that range.
tanv increases throughout [0,3π], so the maximum sits at the right endpoint:
Maximum=tan3π=3Step 5: Confirm the maximum is actually attained.
At v=3π the constraint forces cosu=2cos(π/3)1=1, so u=0, giving α=3π and β=−3π. Check both conditions:
cos3π+cos(−3π)=21+21=1sin3π−sin(−3π)=23+23=3
Both hold, so 3 is genuinely achieved and is the maximum.
Final Answer:3
A polynomial P(x) leaves a remainder 2 when divided by (x−1) and a remainder 1 when divided by (x−2) The remainder when P(x) is divided by (x−1)(x−2) is
A3−x
B3
Cx−3
D2
Pick an option to attempt
The Setup: A polynomial P(x) leaves specific remainders when divided by two linear binomials. We must use the Polynomial Remainder Theorem to deduce the linear remainder when divided by their quadratic product.
Step 1: Establish the given values using the Remainder Theorem.
The Remainder Theorem states that dividing P(x) by (x−a) yields a remainder of P(a).
* Divided by (x−1), remainder is 2⟹P(1)=2.
* Divided by (x−2), remainder is 1⟹P(2)=1.
Step 2: Formulate the Division Algorithm equation.
When P(x) is divided by a quadratic polynomial (x−1)(x−2), the maximum possible degree of the remainder is linear.
Let the remainder be R(x)=ax+b.
P(x)=Q(x)(x−1)(x−2)+(ax+b)Step 3: Substitute the known x values to create a system of equations.
Substitute x=1:
P(1)=Q(1)(0)(−1)+(a(1)+b)⟹a+b=2
Substitute x=2:
P(2)=Q(2)(1)(0)+(a(2)+b)⟹2a+b=1Step 4: Solve the linear system for a and b.
Subtract the first equation from the second equation:
(2a+b)−(a+b)=1−2a=−1
Substitute a back into the first equation:
−1+b=2⟹b=3
The resulting linear remainder is R(x)=−1x+3=3−x.
Final Answer:3−x