A cistern has two pipes which fill it in 12 mins and 15 mins each. There is a third outlet pipe in the cistern. When all three pipes are working, the cistern fills up in 20 mins. How much time will it take for the cistern to get empty?

20 mins

No worries! We‘ve got your back. Try BYJU‘S free classes today!

30 mins

No worries! We‘ve got your back. Try BYJU‘S free classes today!

40 mins

No worries! We‘ve got your back. Try BYJU‘S free classes today!

50 mins

No worries! We‘ve got your back. Try BYJU‘S free classes today!

10 mins

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

Open in App

Solution

The correct option is E
10 mins

Work done by the outlet pipe in 1 min = $\frac{1}{20} - \frac{1}{12} - \frac{1}{15} = - \frac{1}{10}$

So the outlet pipe will empty the cistern in 10 mins.

Suggest Corrections

Similar questions

Q. A cistern has two inlets A and B which can fill it in 12 hours and 15 hours respectively. An outlet can empty the full cistern in 10 hours. If all the three pipes are opened together in the empty cistern, how much time will they take to fill the cistern completely?

A cistern has two inlets A and B which can fill it in 12 hours and 15 hours respectively. An outlet can empty the full cistern in 10 hours. If all the three pipes are opened together in the empty cistern, how much tiem will they take to fill the cistern completely?

Q. A cistern has two taps which fill it in 12 minute and 15 minutes respectively. There is also a waste in the cistern. When all the pipes are opened empty cistern is full 20 minutes. How long waste pipe take to empty a full cistern?

Q. A cistern has two taps which fill it in