77
Q:

# Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The number of hours taken by C alone to fill the tank is:

 A) 10 B) 12 C) 14 D) 16

Explanation:

Part filled in 2 hours = 2/6=1/3

Remaining part =$1-13=23$

(A + B)'s 7 hour's work = 2/3

(A + B)'s 1 hour's work = 2/21

C's 1 hour's work = { (A + B + C)'s 1 hour's work } - { (A + B)'s 1 hour's work }

=1/6-2/21 = 1/14

C alone can fill the tank in 14 hours.

Q:

Pipes A and C can fill an empty cistern in 7 and 10.5 hours, respectively while Pipe B can drain the filled cistern in 5.25 hours. If the three pipes are turned on together when the cistern is empty, how many hours will it take for the cistern to be$23$full?

 A) 121 B) 12 C) 14 D) 15.75

Explanation:

1 200
Q:

Pipes A, B and C are attached to an empty cistern. While the first two can fill the cistern in 6.6 and 16.5 hours respectively, the third can drain the cistern, when filled, in 9.9 hours. If all the three pipes are opened simultaneously when the cistern is three-fifths full, how many hours will be needed to fill the cistern?

 A) 3.5 B) 4 C) 3.6 D) 3.75

Explanation:

0 238
Q:

Two pipes A and B can fill an empty cistern in 1.8 and 2.7 hours, respectively. Pipe C can drain the entire cistern in 4.5 hours when no other pipe is in operation. Initially when the cistern was empty Pipe A and  Pipe C were turned on. After a few hours Pipe A was turned off and Pipe B was turned on instantly. In all it took 5.5 hours to fill the cistern. For how many hours was Pipe B turned on?

 A) 5 B) 4.5 C) 3 D)

Explanation:

0 294
Q:

Pipe A could fill an empty cistern in 18 hrs while pipe B can drain a filled cistern in 30 hrs. When the cistern is empty, pipe A is turned on for an hour and then turned off. The pipes were alternately left open for an hour each time till the cistern was full. How much time did it take for the cistern to be full?

 A) 90 hrs B) 86 hrs 40 min C) 45 hrs D) 86 hrs 48 min

Explanation:

0 240
Q:

Pipe A can fill an empty cistern in 6 hours while along with Pipe B it can fill it up in 4 hours. Only Pipe B is on for an hour after which Pipe A is also turned on. How much time will it take in all to fill up the cistern?

 A) 4 hrs 25 min B) 4 hrs 15 min C) 4 hrs 40 min D) 4 hrs

Explanation:

0 356
Q:

Pipe C and D alone can fill a tank in 4 and 5 hours, respectively. If pipe C is closed after 3 hours and at the same time pipe D is opened. in how many hours will the tank get filled?

 A) 0.8 B) 1.25 C) 1 D) 1.5

Explanation:

0 418
Q:

One of the two inlet pipes works twice as efficiently as the other. The two, working alongside a drain pipe that can empty a cistern all by itself in 12 hours, can fill the empty cistern in 12 hours. How many hours will the less efficient inlet pipe take to fill the empty cistern by itself?

 A) 9 B) 15 C) 12 D) 18

Explanation:

0 389
Q:

Pipes A and B, when working together, can fill an empty tank in 24 hours. They work together for 8 hours and then B is stopped but A continued to work. It took a total of 28 hours to fill the tank. How long would it take A to fill the empty tank alone?

 A) 30 hours B) 29 hours C) 28 hours D) 31 hours