Pipes and Cisterns Test 2 Last Updated on January 3, 2012 1. Two pipes P and Q can fill a cistern in 10 minutes and 1 5 minutes respectively. But an empty pipe R can empty it in 5 minutes. The pipes P and Q are opened for 4 minutes and the empty pipe R is also opened. In what time will the cistern emptied? a) 10 min b) 20 min c) 15 min d) 12 min2. A cistern is filled by two taps in A and B hours respectively. The emptied by the tap in C hours. If all the three taps are opened simultaneously, the cistern is filled in F hours. The relation between F, A, B and C are given by ________. a) F = (A+B)-C b) F= AxB/c c) 1/F = 1/A+1/B+1/c d) F = 1/1/A+1/B+1/C3. Two pipes P and Q can separately fill a cistern in 12 minutes and 15 minutes respectively. While the third piper can empty it in 6 minutes. The piped P and Q are kept open for 5 minutes, then the pipe R is also opened. In what time the system is emptied. a) 30 min b) 35 min c) 40 min d) 45 min4. Two pipes can P and Q separately can fill a cistern 12 minutes and 24 minutes respectively. An d waste can drain off 20 gallons per minute. If all the three pipes are opened, the tank is filled in 24 minutes. What is the capacity of the tank? a) 360 gallons b) 380 gallons c) 240 gallons d) 320 gallons5. A tank can be filled separately by two pipes P and Q in 45 and 36 minutes respectively. A tap R at the bottom can empty the full cistern in 30 minutes. If the tap R is opened 7 minutes after the two pipes P and Q are opened, Find when the tank becomes full? a) 39 min b) 45 min c) 49 min d) 59 min6. There is a leak in the bottom of the cistern. When there was no leak, the cistern was filled in 2 ½ hours. It now takes half-an-hour longer. If the cistern is full, how long it would take the leakage to empty the tank, If the water leaks out at double the rate after half the cistern becomes empty. a) 10 hrs 15 min b) 11 hrs 15 min c) 12 hrs 15 min d) 13 min 7. An empty cistern has three taps P, Q and R. P and Q can fill it in 3 and 4 hours respectively. R can empty it in one hour. If P,Q and R are kept opened at 1 P.M.,2 P.M., and 3 P.M., respectively, fine when the system will be empty? a) 3:20 PM b) 5:20 PM c) 5:12 PM d) 6:20 PM8. An electric pump can fill a tank in 3 hours. Because of a leak, it took 3 ½ hours to fill the tank. In how much time the leak can drain the full tank? a) 21 hrs b) 20 hrs c) 32 hrs d) 25 hrs9. Two pipes P and Q can fill a cistern in 1 hour and 75 minutes respectively. There is also an outlet R. If all three pipes are opened together, the tank is full in 50 minutes. How much time will be taken by R to empty the full tank? a) 50 min b) 70 min c) 100 min d) 120 min10. Two pipes P and Q can fill a cistern in 24 minutes and 32 minutes respectively, after how much should Q be closed so that the tank is full in 18 minutes? a) 8 min b) 12 min c) 15 min d) 13 min

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