81). Two pipes can, fill a cistern separately in 24 minutes and 40 minutes respectively and a waste pipe can drain off 30 litres per minute. If all the three pipes open, the cistern fills in one hour. What is the capacity of cistern.
| A). 600 litres |
| B). 450 litres |
| C). 500 litres |
| D). 900 litres |
|
82). A tank can be filled by two pipes in 20 minutes and 30 minutes respectively when the tank was empty, two pipes were opened. After sometime, the first pipe was stopped and the tank was filled in 18 minutes. After how much time of the start was the first pipe stopped.
| A). 5 minutes |
| B). 8 minutes |
| C). 10 minutes |
| D). 12 minutes |
|
83). Two pipes P and Q would fill a cistern in 24 hours and 32 hours respectively. If both pipes are opened together find when the first pipe must be turned off so that the cistern must be filled in 16 hours.
| A). 12 minutes |
| B). 6 minutes |
| C). 18 minutes |
| D). 16 minutes |
|
84). Two pipes P and Q can fill a cistern in 24 minutes and 32 minutes respectively. Both are opened together, but at the end of 4 minutes. Q is turned off. The cistern will be full in
| A). 16 minutes |
| B). 24 minutes |
| C). 21 minutes |
| D). 18 minutes |
|
85). A cistern can be filled by two pipes A and B in 24 minutes and 32 minutes respectively. C can empty it in 12 minutes. If A and B are opened first and after 6 minutes, tap C is also opened. The tank is emptied in
| A). 36 minutes |
| B). 24 minutes |
| C). 48 minutes |
| D). 54 minutes |
|
86). A tap A fills a tank in 15 hours and another tank B empties in 30 hours. If both are open, in how many hours the tank will be full?
| A). 30 hours |
| B). 15 hours |
| C). 25 hours |
| D). 60 hours |
|
87). Two pipes A and B can fill a tank in 20 minutes and 30 minutes respectively. If both pipes are opened together, the time taken to fill the tank is:
| A). 50 minutes |
| B). 12 minutes |
| C). 25 minutes |
| D). 15 minutes |
|
88). If \( \Large \frac{1}{3} \) of a tank holds 80 litres of water, then the quantity of water that \( \Large \frac{1}{2} \) of tank holds is:
| A). 240 litres |
| B). 120 litres |
| C). \( \Large \frac{80}{3} \) litres |
| D). 100 litres |
|
89). Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are opéned for one hour each alternatively, the tank will be full in :
| A). 6 hours |
| B). \( \Large 6\frac {1}{2} \) hours |
| C). 7 hours |
| D). \( \Large 7\frac {1}{2} \) hours |
|
90). A pipe of diameter 'd' can drain a certain water tank in 40 minutes. The time taken by a pipe of diameter '2d' for doing the same job in :
| A). 5 minutes |
| B). 10 minutes |
| C). 20 minutes |
| D). 80 minutes |
|
