6.

Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:

 A. 60 gallons B. 100 गैलन C. 120 गैलन D. 180 गैलन

7.

A tank is filled in 5 hours by three pipes A, B and C. The pipe C is twice as fast as B and B is twice as fast as A. How much time will pipe A alone take to fill the tank?

 A. 20 hours B. 25 घंटे C. 35 घंटे D. तय नहीं किया जा सकता

8.

Two pipes A and B together can fill a cistern in 4 hours. Had they been opened separately, then B would have taken 6 hours more than A to fill the cistern. How much time will be taken by A to fill the cistern separately?

 A. 1 hour B. 2 घंटे C. 6 घंटे D. 8 घंटे

9.

Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank?

 A. 10 min. 20 sec. B. 11 मिनट। 45 सेकंड। C. 12 मिनट। 30 सेकंड। D. 14 मिनट। 40 सेकंड।

10.

Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?

 A. 12 min B. 15 मिनट C. 25 मिनट D. 50 मिनट