A wall clock moves 10 minutes fast in every 24 hours. The clock was set right to show the correct time at 8:00 a.m. on Monday. When the clock shows the time 6:00 p.m. on Wednesday, what is the correct time?
- A.5:36 pm
- B.5:30 pm
- C.5:24 pm
- D.5:18 pm
▶ Answer & Explanation
Correct answer: A. 5:36 pm
The clock gains 10 minutes in 24 hours, meaning for every 24 hours of actual time, the clock shows 24 hours and 10 minutes. The total time elapsed from 8:00 a.m. Monday to 6:00 p.m. Wednesday is 58 hours. The gain in time over 58 hours can be calculated proportionally. Since the clock gains 10 minutes in 24 hours, it gains (10/24) minutes per hour. Over 58 hours, the total gain is (10/24) * 58 minutes. This calculated gain needs to be subtracted from the time shown on the faulty clock (6:00 p.m. Wednesday) to find the correct time.
Source: UPSC csat 2019