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Aptitude - Pipes & Cisterns Online Quiz
Following quiz provides Multiple Choice Questions (MCQs) related to Pipes & Cisterns. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.
Q 1 - A tap can fill storage in 8 hours and another tap can discharge it in 16 hours. In the event that both the taps are open, the time taken to fill the tank will be:
Answer : C
Explanation
Net part filled in 1 hr = (1/8 ? 1/16)= 1/16 Total time taken to fill the tank = 16 hrs.
Q 2 - A pump can fill a tank with water in 2 hours. In light of a break in the tank, it takes 7/3 hours to fill the tank. The hole can discharge the filled tank in:
Answer : D
Explanation
Part filled by the pump in 1 hr = 1/2 Net part filled by the pump and leak in 1 hr = 3/7 Emptying work done by the leak in 1 hr= (1/2 - 3/7)= 1/14 Leak can empty the tank in 14 hours.
Q 3 - A storage has two funnels. One can fill it with water in 8hours and the other can exhaust it in 5 hours. In how long will the reservoir be purged if both the channels are opened together when 3/4 of the storage is now loaded with water?
Answer : C
Explanation
Net part emptied by both in 1 hr = (1/5-1/8)= 3/40 3/40 part is emptied in 1 hr. 3/4 part will be emptied in (40/3*3/4) hrs = 10 hrs.
Q 4 - Two pipes A and B can fill a tank in 15 minutes and 20 minutes separately. Both the channels are opened together. Be that as it may, following 4 minutes, pipe is turned off. What is the aggregate time required to fill the tank?
Answer : D
Explanation
Part filled by both in 4 min. = 4*(1/15+1/20)= (4*7/60)= 7/15 Part unfilled = (1-7/15) = 8/15 1/20 part is filled by B in 1 min. 8/15 part is filled by B in (20*8/15) min. = 32/3 min = 10 min 40 sec. Total time taken = (4 min+10 min 40 sec.) = 14 min 40 sec.
Q 5 - Two pipes A and B can fill a reservoir in 6 minutes and 7 minutes separately. Both the funnels are opened then again for 1 minute each. In what the reality of the situation will become obvious eventually fill the storage?
Answer : C
Explanation
Part filled by A in 1st min and B in 2nd min =(1/6+ 1/7 )= 13/42 Part filled by (A+B) working alternately in 6 min. (1/2 * 13/42*6) = 13/14 Remaining part = (1-13/14) = 1/14 It is now A's turn. 1/6 part is filled in 1 min. 1/14 part is filled in (6*1/14) min = 3/7 min. Total time taken = 45/7 min.
Q 6 - Three funnels A, B; C can fill a tank in 6 hours. In the wake of working at it together for 2 hours, C is shut and A and B can fill the remaining part in 7 hours. The quantity of hours taken by C alone to fill the tank is:
Answer : C
Explanation
Part filled by (A+B+c) in 2 hours= (1/6*2)=1/3 2/3 part is filled by (A+B) in 7 hours. Whole is filled by (A+B) in (7*3/2) hr=21/2hrs. Part filled by C in 1 hour = (1/6-2/21) = 3/42 = 1/14 ∴C alone can fill it in 14 hours.
Q 7 - If two funnels work at the same time, the repository will be filled in 12 hours. One channel fills the store 10 hours quicker than the request. How long does the speedier funnel take to fill the store?
Answer : C
Explanation
Suppose that one pipe takes x hours to fill the reservoir. Than the other pipes takes (x-10) hours. ∴ 1/x+ 1/(x-10) = 1/12 ⇒12(x-10+x)= x(x-10) ⇒x2-34x +120=0 ⇒(x-30) (X-4) =0 ⇒x= 30 or x= 4 So, the faster pipe takes 30 hrs to fill the reservoir.
Q 8 - A cistern has 3 pipes A, B and C. A and B can ill it in 3 hours and 4 hours respectively while C can empty the completely filled cistern in 1 hour. If the pipes are opened in order at 3, 4 and 5 pm respectively, at what time will the cistern be empty?
Answer : A
Explanation
In 2 hours Pipe A will fill = 2/3 tank In 1 hour Pipe B will fill = 1/4 tank Part of tank filled till 5 PM = (2/3) + (1/4) = 11/12 Remaining part = 1 - (11/12) = 1/12 Net part emptied when A, b and C are opened = (1/3) +( 1/4) - 1 = (4+3-12)/12 = -5/12 ∴ 5/12 part is emptied in 1 hour. ∴ 11/12 is emptied in (12/5)*(11/12) = 11/5 = 2 hr 12 min ∴ Tank will be emptied at 7:12 PM.
Q 9 - A cistern has two pipes. One can fill it with water in 8 hours and the other can empty it in 5 hours. In how many hours will the cistern be emptied if the both the pipes are opened together when 3/4 of the cistern is already full of water.
Answer : B
Explanation
Part if cistern emptied in 1 hour = 1/5 - 1/8 = 3/40 3/40 part is emptied in hour. ∴ 3/4 part is emptied in 40/3 * 3/4 = 10 hour
Q 10 - A cistern can be filled by two pipes in 20 and 30 min respectively. Both pipes being open, when must the first pipe be turned off so that so that the cistern may be filled in 10 min more?
Answer : D
Explanation
In 1 min both pipes can fill = 1/20 + 1/30 = 1/12 In 10 min second pipe can fill = (1/30)*10 = 1/3 part Part of cistern filled by both the pipes = 1 - 1/3 = 2/3 1/12 part is filled in 1 min ∴ 2/3 part will be filled in 12*2/3 = 8 min Hence, first first pipe should be turned off after 8 min.