Question

Two pipes A and B can fill a cistern in 37 1/2 minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if the pipe B is turned off after?

Answer 1

Answer:

Part filled by pipe A in 1 minute

=

2

75

Part filled by pipe B in 1 minute

=

1

45

Suppose pipe B is closed after

x

minutes. Then,

2

75

×

30

+

1

45

×

x

=

1

4

5

+

x

45

=

1

x

=

9