Q1:jipmat 2025QA › Mixture & AlligationMediumQA · MCQ

The ratios of copper to zinc in alloys A and B are 3:4 and 5:9, respectively. If A and B are taken in ratio 2:3 and melted to form new alloy C, then the ratio of copper to zinc in C is:

• A8:13
• B3:5
• C9:11
• D27:43

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The Setup: We are mixing two different alloys like mixing tracks. To avoid terrifying fractions, we need to pick weights for A and B that are easily divisible by their internal ratio sums. Step 1: Analyze the parts. Alloy A parts: $3+4=7$. Alloy B parts: $5+9=14$. The LCM of 7 and 14 is 14. We want to mix them in a $2:3$ ratio. Let's make the multiplier $14$ to keep things clean. Weight of A we use $=2 \times 14=28\text{ units}$. Weight of B we use $=3 \times 14=42\text{ units}$. Step 2: Break down Alloy A into Copper and Zinc. Copper in A $=\frac{3}{7} \times 28=12$. Zinc in A $=\frac{4}{7} \times 28=16$. Step 3: Break down Alloy B into Copper and Zinc. Copper in B $=\frac{5}{14} \times 42=15$. Zinc in B $=\frac{9}{14} \times 42=27$. Step 4: Combine them for the ultimate Alloy C. Total Copper $=12+15=27$. Total Zinc $=16+27=43$. The final ratio of Copper to Zinc in C is exactly $27:43$. Final Answer: 27:43