Question

There are two pipes in a tank. If pipes A an B is opened together the tank will be filled in 20 minutes. If pipe A a alone is opened the tank will be filled in 25 minutes if pipe B alone is opened the tank will be filled in how many minutes ?

• A. 1 hour 20 minutes
• B. 1 hour 50 minutes
• C. 1 hour 40 minutes
• D. 1 hour 30 minutes

Answer 1

Answer:

C. 1 hour 40 minutes

Total capacity of tank = LCM[20, 25] = 100

Efficiency of A + B= 100/20 = 5

Efficiency of A = 100/25 = 4

Efficiency of B = 5 - 4 = 1

Time taken by B to fill the tank = 100/1

= 100 minute

= 1 hour 40 minutes