Question

A normal clock loses 3 minutes per hr and another clock gains 5 min per hr. How many hours after from now, both the clocks will show the correct time simultaneously?

Answer 1

What is the starting point?

Answer 2

assuming they both show the correct time now, then since the fast clock gains 8 minutes per hour, it will gain an hour every 7.5 hours, and the minute hands will be aligned. It will gain 2 hours in 15 hours. Thus, after 6*15=90 hours, it will have gained 12 hours, and the clocks will again show the same time.