Quantitative Aptitude 41-(Pipes and Cisterns)

1. Two pipes A and B are opened together to fill a tank. Both fill the tank in a certain time. If A separately takes 16 min more than the time time taken by (A+B) and B takes 9 min more than the time taken by (A+B). Find the time taken by A and B to fill the tank when both the pipes are opened together.

(a) 10 min

(b) 12 min

(c) 15 min

(d) 8 min

(e) None of these

2. A cistern has three pipes A, B and C. Pipes A and B can fill it in 3 and 4 h, respectively. While pipe C can empty the completely filled in cistern in 1 h. If the pipes are opened in order at 3 pm, 4 pm and 5 pm, respectively. at what time will the cistern be empty?

(a) 6:15 pm

(b) 7:12 pm

(c) 8:12 pm

(d) 8:35 pm

(e) None of these

3. A pipe P can fill a tank in 12 min and another Pipe R can fill it in 15 min. But the 3rd Pipe M can empty it in 6 min. The 1st two pipes P ans R are kept open for double the 2.5 min in the beginning and then the 3rd pipe is also opened. In what time is the tank emptied?

(a) 30 min

(b) 25 min

(c) 45 min

(d) 35 min

(e) None of these

4. Two taps A and B can fill a tank in 25 min and 20 min respectively. But taps are not opened properly . so the tap A and B allow 5/6th and 2/3 rd part of water, respectively.How long will they take to fill the tank?

(a) 12 min

(b) 13 min

(c) 14 min

(d) 15 min

(e) 16 min

5. Two taps A and B can fill a tank in 20 min and 30 min, respectively. An outlet pipe C can empty the full tank in 15 min. A, B and C are  opened alternatively each for 1 min. How long will the tank taken to be filled?

(a) 105 min

(b) 120 min

(c) 167 min

(d) 185 min

(e) 198 min


  1. (b)
  2. (b)
  3. (c)
  4. (d)
  5. (c)