- A1:00 am on Thursday
- B5:00 pm on Wednesday
- C1:00 pm on Wednesday
- D5:00 am on Wednesday
The Setup: We need to calculate the total time elapsed and the total time gained by the faulty watch to figure out exactly when it crossed the threshold of the correct time.
Step 1: Calculate the total time and total gain
* From Tuesday 1 p.m. to Thursday 1 p.m. is exactly 48 hours.
* The watch goes from being 1 minute slow () to 2 minutes fast ().
* Total time gained = minutes.
So, the watch gains 3 minutes every 48 hours.
Step 2: Dox the correction point
Since the watch started exactly 1 minute slow, it needs to gain exactly 1 minute to show the correct time.
* If it gains 3 minutes in 48 hours...
* It gains 1 minute in hours.
Step 3: Secure the target time
We just add 16 hours to the starting time (Tuesday 1 p.m.).
* Tuesday 1 p.m. + 12 hours = Wednesday 1 a.m.
* Wednesday 1 a.m. + 4 hours = Wednesday 5 a.m.
Final Answer: 5:00 am on Wednesday