Question

Give me this answer
a cistern has 2 inlets A and B which can fill in it 12 minutes and 15 minutes respectively in outlet C can ampty the Fud cistern in 10 minutes .if all the 3 pipes are opened together in the empty tank, how much time will they take to fill the tank completely ??​

Answer 1

Answer:

Lets calculate contribution of each inlet to fill the cistern,

we will use negative contribution for inlet emptying the cistern.

Let total volume of cylinder be 1 unit.

A's one minute contribution=

12

1

B's one minute contribution=

15

1

C's one minute contribution=−

10

1

(A+B+C)'s one minute contribution in filling the tank=

12

1

+

15

1

−

10

1

=

60

(5+4−6)

=

20

1

Time taken by A+B+C to fill 1 unit of volume=

1/20

1

min=20min