Question

A cistern can be filled by a tap in 3 hours while it can be emptied by another tap in 8 hours. if both the taps are opened simultaneously, then after how much time will the cistern get filled?

Answer 1

time taken to fill in one hour=1/3
time taken to empty in one hour=1/8
=1/3-1/8
=8-3/24
=5/24
answer is 24/5 hours