Pipes and Cisterns Practice Test 2 with solutions

Before B was closed, A worked for 6 hours and B worked for 2 hours.
Part of tank filled by A in 6 hours =

1

8

×6 =

3

4

Part of tank emptied by B in 2 hours = 2×

1

3

=

2

3

Part of tank filled in 6 hours by A and B =

3

4

−

2

3

=

9−8

12

=

1

12

Part of the tank that is to be filled =

11

12

Complete tank filled by A alone = 8 hours
So, time taken to fill

11

12

th part of the tank by A alone = 8×

11

12

=

22

3

= 7

1

3

hours.