App Logo

No.1 PSC Learning App

1M+ Downloads
Two pipes A and B can fill a tank in 6 hours and 9 hours respectively. They are opened alternately for 1 hour each starting with pipe A first. In how many hours the tank will be filled?

A5

B4

C6

D7

Answer:

D. 7

Read Explanation:

Capacity of the tank = LCM of the time taken by A and B. Capacity of the tank = 18 A’s efficiency = 18/6 = 3 B’s efficiency = 18/9 = 2 2 hours work for A and B = (3 + 2) = 5 6 hours = 15 units 7 hours = 18 units. (At last A fills remaining 3 units) Tank will be filled in 7 hours.


Related Questions:

How many men will be required to plough 50 acres of land in 10 days if 15 men are required 6 days to plough 10 acres of land?
A and B can together complete a task in 18 hours. After 6 hours A leaves. B takes 36 hours to finish rest of the task. How many hours would A have taken to do the task, if he worked alone?
10 men can finish a piece of work in 10 days, whereas it takes 12 women to finish it in 10 days. If 15 men and 6 women undertake to complete the work, how many days will they take to complete it ?
K alone can complete a work in 20 days and M alone can complete the same work in 30 days. K and M start the work together but K leaves the work after 5 days of the starting of work. In how many days M will complete the remaining work?
A tap can fill a tank in 48 minutes, where as another tap can empty it in 2 hours. If both the taps are opened at 11:40 am then the tank will be filled at