Two pipes A and B can fill a tank in 60 minutes and 75 minutes respectively

Two pipes A and B can fill a tank in 60 minutes and 75 minutes respectively. There is also an outlet C. If A, B and C are opened together, the tank is full in 50 minutes. How much time will be taken by C to empty the full tank?
(a) 100 minutes
(b) 110 minutes
(c) 120 minutes
(d) 125 minutes

Anurag Mishra Professor Asked on 19th February 2016 in Maths.
Add Comment
1 Answer(s)

Answer: (a) 100 minutes

Solution:-
A pipe can fill a tank = 60 minutes
Therefore, A pipe can fill a tank in minute = 1/60

B pipe can fill a tank = 75 minutes 
Therefore, B pipe can fill a tank in a minute = 1/75

A, B and C together can fill a tank = 50 minutes
Therefore, A, B and C can fill a tank in a minute = 1/50

Thus, C pipe can empty a tank in minute = 1/50 – (1/60 + 1/75)
 = {6 – (5 + 4)}/300
 = -3/300
 = 1/100

Therefore, C pipe can empty same tank = 100 minutes. 

Hence, the correct answer is option (a) 100 minutes. 

Anurag Mishra Professor Answered on 19th February 2016.
Add Comment

Your Answer

By posting your answer, you agree to the privacy policy and terms of service.