Management Aptitude Test 2015 Paper

(b) Given, pipe A can fill a tank in 30 min,
B and C can fill the tank In 90 min
and A and B can fill the tank in 20 min.
Now, pipe B alone can fill the tank in
=

1

A+B

−

1

A

=

1

20

−

1

30

=

3−2

60

=

1

60

And pipe C alone can empty the tank in
=

1

B+C

−

1

B

=

1

90

−

1

60

=

2−3

180

=−

1

180

Here, negative sign means empty.
So, the pipe C can empty the tank in 180 min.