Question

An analog clock loses 2 minutes every 3 hours. What is the shortest interval of time after which the clock will show the correct time?

Answer 1

1152 hours - 42 days =)

Explanation:

Answer 2

In order to show the correct time again, the clock has to be exactly 12 hours, or 12*60=720 minutes, behind. With 2 minutes per 3 hours, the clock will have to run for 3 * 720/2 = 1080 hours. 1080 hours = 45 days. The shortest interval the clock need to show the correct time is 45 days.