Question

pipe A can fill a tank in 5 hours and pipe B can fill it in 15 hours both the pipes are opened and after 2 hour pipe A is closed in how much time will be alone fill the remaining part of the tank.......... Pls tell full solution

Answer 1

Pipe A = 1/ 5

Pipe B = 1/15

adding both

1/5 + 1/15 =  3+1/15 = 4/15

Now the after 2 hour Pipe A was close.

4/15 - 1 = 11/15   (pipe B is still running)

11/15-1/2 =  7/30 (pipe A is closed)

Approx. answer is 4 hour.