Question

A cistern has two pipes one of which pours in 4/15 litre of water and the other empties 2/3 little every minute. the cistern has 36 litre of water ; when will it be emptied if both the pipes are opened at a time?​

Answer 1

Answer:

Part of the tank filled by the first pipe in 1 hour =

8

1

Part of the tank emptied by the second pipe in 1 hour =

5

1

∴ Part of the tank emptied when both the pipes are opened together =

5

1

−

8

1

=

40

3

∴

40

3

part of the tank is emptied in 1 hour

∴

4

3

th of the tank will be emptied in (

3

40

×

4

3

) hours =10 hours.