Question

A cistern can be filled by a tap in 4 hrs and emptied by an outlet pipe in 6 hours how long will it take to fill the cistern if both tap are opened together ?please and with full statement

Answer 1

Cistern filled in one hour = 1/4
Cistern emptied in one hour = 1/6
Time taken to fill the cistern if both taps are opened => 1/4-1/6 = 1/12 in one hour
Total time taken to fill the cistern = 1/1/12 = 12 hour

Answer 2

A cistern can be filled by a tap in 4 hrs
A cistern can be filled by a tap in 1 hr = 1/4
A cistern emptied by an outlet pipe in 6 hrs
A cistern emptied by an outlet pipe in 1 hr =1/6
Time taken to fill the cistern if both taps are opened together in 1 hr = 1/4-1/6=1/12
Total time taken to fill the cistern = 12 hrs.