Question

Two pipes, A and B, can fill a tank in 3 and 4 hours, respectively. Another pipe, C, can empty the filled tank in 6 hours. If A and B are opened at 8 AM and run for 1.5 hours and then C is opened as well, calculate the time when the tank will be fully filled:​

Answer 1

Answer:

A 'work in 1 hour =

6

1

and B

′

s work in 1 hour =

4

1

⇒ (A+B)

′

s 2 hour's work when opened alternately =

6

1

+

4

1

=

12

5

.

⇒ (A+B)

′

s 4 hour's work when opened alternately =

12

10

=

6

5

⇒ Remaining part =1−

6

5

=

6

1

Now, it is A

′

s turn and

6

1

part is filled by A in 1 hour.

∴ Total time taken to fill the tank =(4+1)hrs=5hrs