Question

two pipes can fill a tank in 30 minutes and 40 minutes respectively.third pipe can empty the tank in 24 minutes.if all the pipes kept open the tank can be filled in​

Answer 1

Answer:

60 minutes

Step-by-step explanation:

Two pipe can fill a tank in 30 minutes, 40 minutes

So, Portion of work done by two pipes n 1 minute would be ( 1 / 30 ) and ( 1 / 40 )

Third pipe can empty the tank in 24 minutes

Portion of work done by 3rd pipe in 1 minute = 1 / 24

If all pipes kept open

Portion of work done by all pipes together in 1 minute :

⇒ ( 1 / 30 ) + ( 1 / 40 ) - ( 1 / 24 )

[ + sign represent filling an - sign represent emptying ]

⇒ ( 4 + 3 - 5 ) / 120

⇒ 2 / 120

⇒ 1 / 60

Therefore tank can be filled in 60 minutes.

Answer 2

Solution:

Time taken by pipe A to fill the tank=30 minutes

Time taken by pipe B to fill the tank=40 minutes

Time taken by pipe C to empty the tank=24 minutes

Work done by pipe A in 1minute=1/30

Work done by pipe B in 1minute=1/40

Work done by pipe C in 1minute=1/24

Work done by pipe A,B and C together=1/30 +1/40-1/24

=4+3-5/120

=2/120

=1/60

Time taken by pipe A,B and C together=60

minutes.