Question

A cistern can be filled by pipes A and B in 4 hours and 6 hours respectively. When full
, the cistern
can be emptied by a pipe C in 8 hours. If all the pipes be turned on at the same time, the cistern
will be full in
​

Answer 1

In 1 hour A will fill the pipe by 1/4 part.

In 1 hour B will fill the pipe by 1/6 part.

So, In 1 hour (A+B) will fill the pipe by 1/4+1/6 = (3+2)/12 = 5/12 part.

So, In 1 hour C will empty the pipe by 1/8 part.

So, the cistern will fill by 5/12 - 1/8 = (10-3)/24 = 7/24 part.

Therefore, the pipe will be full in 24/7 = 3 hours and 7 minutes and 5 seconds.

Answer 2

Answer:

but I am not cute like you