DRDO Multi tasking staff Model paper 2

Since, both the pipes are opening one by one.
So, in 2 minutes, part of Tank will be filled =

1

6

+

1

8

=

7

24

So, in 6 minutes 3 × 7/24 = 21/24 part will be filled.
Remaining part = 1 – 21/24 = 1/8 part
Now it’s A’s turn to fill the tank. SO time taken to fill 1/8 part =

1 6

1 8

=

3

4

min
So, Total time 6

3

4

mins.