Question

1. Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes
are used together, then how long will it take to fill the tank ? (M.A.T, 2003)
(b) 15 min
(c) 25 min
(d) 50 min
(a) 12 min​

Answer 1

Answer:

Part of tank filled by 1st pipe in 1 minute =

20

1

Part of tank filled by 2nd pipe in 1 minute =

30

1

∴ Part of tank filled by both the pipes in 1 minute =(

20

1

+

30

1

)=

60

5

=

12

1

Time taken to fill the tank =12 minutes.