In this aptitude test, we have selected 45 Pipes and Cistern questions to practice. Think of every pipe as a “work rate” machine for filling or emptying. You’ll handle combined pipes, leakage, and time taken puzzles. Each question includes an answer.
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45 Pipes and Cistern Aptitude Questions with Answers (Solved)
Question 1. Pipe A can fill a tank in 12 hours and Pipe B can fill it in 18 hours. How long will they take together?
a) 6 hours
b) 7 hours 12 minutes
c) 8 hours
d) 9 hours
Answer:
b) 7 hours 12 minutes
Question 2. A pipe can fill a tank in 10 hours. A leak can empty the full tank in 15 hours. If both are open, how long will the tank take to fill?
a) 20 hours
b) 25 hours
c) 30 hours
d) 35 hours
Answer:
c) 30 hours
Question 3. Pipe A fills a tank in 8 hours and Pipe B fills it in 12 hours. An outlet C can empty it in 24 hours. If A, B and C are opened together, how long will it take to fill the tank?
a) 5 hours
b) 6 hours
c) 7 hours
d) 8 hours
Answer:
b) 6 hours
Question 4. Two pipes together fill a tank in 4 hours. One of the pipes alone can fill the tank in 6 hours. How long will the other pipe alone take?
a) 8 hours
b) 10 hours
c) 12 hours
d) 14 hours
Answer:
c) 12 hours
Question 5. Pipe A fills a tank in 9 hours and Pipe B fills it in 18 hours. How long will they take together?
a) 5 hours
b) 6 hours
c) 7 hours
d) 8 hours
Answer:
b) 6 hours
Question 6. Pipe A can fill a tank in 16 hours. Pipe B can empty the full tank in 24 hours. If both are opened, how long will it take to fill the tank?
a) 24 hours
b) 32 hours
c) 40 hours
d) 48 hours
Answer:
d) 48 hours
Question 7. Pipes A and B together fill a tank in 6 hours. Pipe A alone fills it in 10 hours. How long will Pipe B alone take?
a) 12 hours
b) 15 hours
c) 18 hours
d) 20 hours
Answer:
b) 15 hours
Question 8. Pipe A fills a tank in 20 hours. Pipe B empties it in 30 hours. The tank is already 1/3 full. If both are opened, how long will it take to fill the tank completely?
a) 20 hours
b) 30 hours
c) 40 hours
d) 60 hours
Answer:
c) 40 hours
Question 9. Pipe A fills a tank in 14 hours and Pipe B fills it in 21 hours. How long will they take to fill 3/5 of the tank together?
a) 4 hours 48 minutes
b) 5 hours 2 minutes
c) 5 hours 30 minutes
d) 6 hours
Answer:
b) 5 hours 2 minutes
Question 10. Pipe A fills a tank in 12 hours and Pipe B fills it in 16 hours. A is opened alone for 2 hours, then B is also opened. How long (total) will it take to fill the tank?
a) 7 hours
b) 7 hours 15 minutes
c) 7 hours 43 minutes
d) 8 hours
Answer:
c) 7 hours 43 minutes
Question 11. Pipe A fills a tank in 6 hours. An outlet empties it in 8 hours. If both are opened, how long will it take to fill the tank?
a) 12 hours
b) 18 hours
c) 24 hours
d) 36 hours
Answer:
c) 24 hours
Question 12. Pipe A fills a tank in 15 hours, Pipe B fills it in 20 hours and Pipe C empties it in 30 hours. If all are opened together, how long will it take to fill the tank?
a) 10 hours
b) 12 hours
c) 15 hours
d) 18 hours
Answer:
b) 12 hours
Question 13. Two pipes together fill a tank in 5 hours. They run together for 2 hours and then only one pipe continues and fills the remaining tank in 4 hours. How long would that pipe alone take to fill the tank?
a) 5 hours
b) 6 hours
c) 6 hours 40 minutes
d) 8 hours
Answer:
c) 6 hours 40 minutes
Question 14. Pipe A fills a tank in 9 hours. Pipe B empties it in 12 hours. A is opened for 3 hours, then B is also opened. How long (total) will it take to fill the tank?
a) 18 hours
b) 24 hours
c) 27 hours
d) 36 hours
Answer:
c) 27 hours
Question 15. Pipe B fills a tank in 8 hours. If 25% of the tank is already filled, how long will B take to fill the remaining?
a) 4 hours
b) 5 hours
c) 6 hours
d) 7 hours
Answer:
c) 6 hours
Question 1. Pipe A fills a tank in 10 hours and Pipe B fills it in 15 hours. A runs for 2 hours, then both run for 3 hours, then only B runs. How long (total) to fill the tank?
a) 8 hours 30 minutes
b) 9 hours
c) 9 hours 30 minutes
d) 10 hours
Answer:
c) 9 hours 30 minutes
Question 2. Pipe A fills a tank in 12 hours. An outlet empties it in 18 hours. A runs alone for 3 hours, then the outlet is opened too. How long (total) to fill the tank?
a) 18 hours
b) 24 hours
c) 30 hours
d) 36 hours
Answer:
c) 30 hours
Question 3. Pipe A fills a tank in 6 hours and Pipe B fills it in 8 hours. An outlet C empties it in 12 hours. A and B start together. After 2 hours, C is also opened. How long (total) to fill the tank?
a) 3 hours
b) 4 hours
c) 5 hours
d) 6 hours
Answer:
b) 4 hours
Question 4. Pipe A fills a tank in 9 hours and Pipe B fills it in 12 hours. Both are opened together, but after 3 hours B is closed. How long (total) to fill the tank?
a) 6 hours 15 minutes
b) 6 hours 45 minutes
c) 7 hours 15 minutes
d) 7 hours 45 minutes
Answer:
b) 6 hours 45 minutes
Question 5. A tank is 40% full. An inlet fills the full tank in 10 hours and an outlet empties the full tank in 15 hours. If both are opened, how long to fill the tank completely?
a) 12 hours
b) 15 hours
c) 18 hours
d) 20 hours
Answer:
c) 18 hours
Question 6. Pipe A fills a tank in 8 hours and Pipe B fills it in 16 hours. They are opened alternately every hour starting with A (A for 1 hour, then B for 1 hour, and so on). How long will it take to fill the tank?
a) 9 hours
b) 10 hours
c) 10 hours 30 minutes
d) 11 hours
Answer:
c) 10 hours 30 minutes
Question 7. Pipe A fills a tank in 12 hours and Pipe B empties it in 18 hours. A runs for 4 hours, then B runs alone for 3 hours, then both are opened together. How long (total) to fill the tank?
a) 30 hours
b) 33 hours
c) 37 hours
d) 40 hours
Answer:
c) 37 hours
Question 8. Pipe A fills a tank in 20 hours and Pipe B fills it in 30 hours. Both start together. After 6 hours, A is closed. How much more time will B take to fill the remaining tank?
a) 10 hours
b) 12 hours
c) 15 hours
d) 18 hours
Answer:
c) 15 hours
Question 9. Pipe A fills a tank in 6 hours and Pipe B empties it in 9 hours. Starting from empty, A runs for 1 hour, then B is also opened. How long (total) to fill the tank?
a) 10 hours
b) 12 hours
c) 14 hours
d) 16 hours
Answer:
d) 16 hours
Question 10. Pipe A fills a tank in 15 hours and Pipe B fills it in 20 hours. Both fill the first half together, then only A fills the second half. How long (total) to fill the tank?
a) 10 hours 30 minutes
b) 11 hours 47 minutes
c) 12 hours 30 minutes
d) 13 hours
Answer:
b) 11 hours 47 minutes
Question 11. Pipe A fills a tank in 8 hours, Pipe B fills it in 12 hours, and outlet C empties it in 24 hours. A and B run for 2 hours. Then C is opened too for 2 hours. After that, A is closed (B and C continue). How long (total) to fill the tank?
a) 8 hours
b) 9 hours
c) 10 hours
d) 12 hours
Answer:
c) 10 hours
Question 12. Pipe A fills a tank in 9 hours and Pipe B fills it in 18 hours. A leak starts after 3 hours and can empty the full tank in 36 hours. How long (total) to fill the tank?
a) 6 hours
b) 6 hours 36 minutes
c) 7 hours
d) 7 hours 30 minutes
Answer:
b) 6 hours 36 minutes
Question 13. A tank is full. An outlet can empty it in 10 hours. An inlet can fill it in 15 hours. The outlet is opened for 2 hours, then the inlet is also opened (both continue). How long (total) until the tank becomes empty?
a) 14 hours
b) 20 hours
c) 24 hours
d) 26 hours
Answer:
d) 26 hours
Question 14. Pipe A fills a tank in 12 hours and Pipe B fills it in 16 hours. A runs for 2 hours, then B runs alone for 3 hours, then both run together. How long (total) to fill the tank?
a) 8 hours 40 minutes
b) 9 hours 10 minutes
c) 9 hours 26 minutes
d) 10 hours
Answer:
c) 9 hours 26 minutes
Question 15. Pipe A fills a tank in 6 hours, Pipe B fills it in 8 hours, and outlet C empties it in 12 hours. If all three are opened together, how long will they take to fill 75% of the tank?
a) 3 hours
b) 3 hours 20 minutes
c) 3 hours 36 minutes
d) 4 hours
Answer:
c) 3 hours 36 minutes
Question 1. Tank A has twice the capacity of Tank B. A pipe fills Tank A in 12 hours. How long will the same pipe take to fill Tank B?
a) 4 hours
b) 6 hours
c) 8 hours
d) 10 hours
Answer:
b) 6 hours
Question 2. A pipe fills Tank A in 10 hours and fills Tank B in 15 hours (same pipe, same flow). What is the ratio of capacities A:B?
a) 2:3
b) 3:2
c) 1:2
d) 3:5
Answer:
a) 2:3
Question 3. A tank has capacity 6000 liters. Pipe A fills at 500 L/min and Pipe B drains at 300 L/min. The tank initially has 1500 liters. If both are opened, how long to fill the tank completely?
a) 18 min
b) 20 min
c) 22.5 min
d) 25 min
Answer:
c) 22.5 min
Question 4. Two inlets fill at 40 L/min and 30 L/min. An outlet drains at 20 L/min. If all are open, how long to fill an empty 9000 L tank?
a) 120 min
b) 150 min
c) 180 min
d) 210 min
Answer:
c) 180 min
Question 5. Pipe A fills a tank in 12 hours and Pipe B fills it in 18 hours. A leak can empty the full tank in 36 hours. If A, B and the leak are all active, how long to fill the tank?
a) 8 hours
b) 9 hours
c) 10 hours
d) 12 hours
Answer:
b) 9 hours
Question 6. Pipes A and B fill a tank in 8 hours, B and C fill it in 12 hours, and A and C fill it in 10 hours. How long will A, B and C take together?
a) 6 hours
b) 6 hours 29 minutes
c) 7 hours
d) 7 hours 30 minutes
Answer:
b) 6 hours 29 minutes
Question 7. Pipe A fills a tank in 14 hours and Pipe B fills it in 21 hours. Outlet C empties it in 42 hours. A and B start together; after 2 hours, C is also opened. How long (total) to fill the tank?
a) 8 hours
b) 9 hours
c) 10 hours
d) 12 hours
Answer:
c) 10 hours
Question 8. DATA SUFFICIENCY: Find the time taken by Pipe A alone to fill the tank.
I. Pipes A and B together fill the tank in 6 hours.
II. Pipe B alone fills the tank in 15 hours.
a) Statement I alone is sufficient
b) Statement II alone is sufficient
c) Both statements together are sufficient, but neither alone
d) Even together, not sufficient
Answer:
c) Both statements together are sufficient, but neither alone
Question 9. DATA SUFFICIENCY: Find what fraction of the tank will be filled in 3 hours when both are open together.
I. The inlet pipe can fill the tank in 12 hours.
II. A leak can empty the full tank in 24 hours.
a) Statement I alone is sufficient
b) Statement II alone is sufficient
c) Both statements together are sufficient, but neither alone
d) Even together, not sufficient
Answer:
c) Both statements together are sufficient, but neither alone
Question 10. DATA SUFFICIENCY: Find the capacity of the tank.
I. A pipe fills at 40 L/min and takes 150 minutes to fill the tank.
II. Another pipe drains at 20 L/min and empties the full tank in 300 minutes.
a) Statement I alone is sufficient
b) Statement II alone is sufficient
c) Both statements together are sufficient, but neither alone
d) Even together, not sufficient
Answer:
a) Statement I alone is sufficient
Question 11. DATA SUFFICIENCY: Find the time taken by A, B and C together to fill the tank.
I. A and B together fill the tank in 8 hours.
II. B and C together fill the tank in 12 hours.
a) Statement I alone is sufficient
b) Statement II alone is sufficient
c) Both statements together are sufficient, but neither alone
d) Even together, not sufficient
Answer:
d) Even together, not sufficient
Question 12. DATA SUFFICIENCY: Find the time taken to empty a partially filled tank.
I. The outlet empties the full tank in 10 hours.
II. The tank is currently 40% full.
a) Statement I alone is sufficient
b) Statement II alone is sufficient
c) Both statements together are sufficient, but neither alone
d) Even together, not sufficient
Answer:
c) Both statements together are sufficient, but neither alone
Question 13. Pipe A fills a tank in 16 hours and Pipe B fills it in 24 hours. How long will they take together to fill half the tank?
a) 4 hours
b) 4 hours 48 minutes
c) 5 hours
d) 6 hours
Answer:
b) 4 hours 48 minutes
Question 14. Pipe A can fill a tank in 18 hours. Pipe B can empty it in 12 hours. Starting from a full tank, if both are opened, how long will it take to empty the tank?
a) 18 hours
b) 24 hours
c) 30 hours
d) 36 hours
Answer:
d) 36 hours
Question 15. Pipe A fills a tank in 10 hours and Pipe B fills it in 15 hours. An outlet empties it in 30 hours. All three are opened together, but the outlet closes after 3 hours. How long (total) will it take to fill the tank?
a) 6 hours
b) 6 hours 36 minutes
c) 7 hours
d) 7 hours 30 minutes
Answer:
b) 6 hours 36 minutes
