Question

Tap A fills a tank in 20 hours while tap B fill it in 30 hours .If they are opened on alternate hours and if A was opened first, in what time will the tank be full.

Answer 1

since A takes 20 hours and B takes 30 hours thus if we open them together they will take 12 hours.but since we are opening alternatively thus  time taken by those two taps will be 24 hours.

Answer 2

Answer to this question is 24 hrs.