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- Question
- A cistern can be filled by two pipes in 30 and 40 minutes respectively. Both the pipes were opened at once, but after some time the first was shut up and the cistern was filled in 10 minutes more. How long after the pipes had opened was the first pipe shut up?
Options- A. 90/ 11 minutes
- B. 90/7 minutes
- C. 90/13 minutes
- D. 45/2 minute
- Correct Answer
- 90/7 minutes
ExplanationLet the first pipe be shut up after x minutes
Now, applying the given rule, we have 30{1 - (x + 10)/40 } = x
[Here t = (x + 10) minutes]
or x = 90/7 minutes - 1. A cistern can be filled by two pipes. A and B in 12 minutes and 14 minutes respectively and can be emptied by a third pipe C in 8 minutes. If all the taps be turned on at the same moment, what part of cistern will remain unfilled at the end of 7 minutes?
Options- A. 5/24
- B. 19/24
- C. 7/24
- D. 17/24 Discuss
- 2. Top A can fill a water tank in 25 minutes, tap B can fill the same tank in 40 minutes and tap C can empty the tank in 30 minutes. If all the three taps are opened together, in how many minutes will the tank be completely filled up or emptied?
Options- A. 32/13
- B. 155/13
- C. 82/13
- D. 3111/19 Discuss
- 3. A water tank is 2/5th full pipe A can fill the tank in 10 minutes and the pipe B can empty it in 6 minutes. If both the pipes are open, how long will it take to empty or fill the tank completely?
Options- A. 6 minutes to empty
- B. 6 minutes to fill
- C. 9 minutes to empty
- D. 9 minutes to fill Discuss
- 4. Two pipes X and Y can fill a cistern in 24 min. and 32 min. respectively. If both the pipes are opened together, then after how much time Y should be closed so that the tank is full in 18 minutes?
Options- A. 6 min.
- B. 8 min.
- C. 10 min.
- D. 12 min. Discuss
- 5. A leak in the bottom of a tank can empty the full tank in 6 hours. An Inlet pipe fills water at the rate of 4 litres per minute. When the tank is full, the Inlet is opened and due to the leak the tank is empty in 8 hours. The capacity of the tank is?
Options- A. 5260 litres
- B. 5760 litres
- C. 5846 litres
- D. 6970 litres Discuss
- 6. A cistern has a leak which would empty it in 15 hours. A tap is turned on which admits 2 litres per hour into the cistern and it is now emptied in 10 hours. How many litres does the cistern hold?
Options- A. 50 litres
- B. 60 litres
- C. 45 litres
- D. 360 litres Discuss
- 7. There are two tank A and B to fill up a water tank. The tank can be filled in 40 min, if both taps are on. The same tank can be filled in 60 min, if tap A alone is on. How much time will tap B alone take, to fill up the same tank?
Options- A. 64 min
- B. 80 min
- C. 96 min
- D. 120 min Discuss
- 8. Three taps are fitted in a cistern. The empty cistern is filled by the first and the second taps in 3 and 4 h, respectively. The full cistern is emptied by the third tap in 5 h. If all three taps are opened simultaneously, the empty cistern will be filled up in?
Options- A. 114/23 h
- B. 214/23 h
- C. 2 h 40 min
- D. 1 h 56 min Discuss
- 9. Pipe A can fill a Tank in 30 min, while pipe B can fill the same tank in 10 min and pipe C can empty the full tank in 40 min. If all the pipes are opened together, how much time will be needed to make the tank full?
Options- A. 93/13 h
- B. 94/13 h
- C. 97/13 h
- D. 99/13 h Discuss
- 10. Through an inlet, a tank takes 8 h to get filled up. Due to a leak in the bottom, it takes 2 h more to get it filled completely. If the tank is full, how much time will the leak take to empty it?
Options- A. 16 h
- B. 20 h
- C. 32 h
- D. 40 h Discuss
Pipes and Cistern problems
Search Results
Correct Answer: 19/24
Explanation:
Time taken to fill the whole tank = (12 x 14 x 8) / (14 x 8 + 12 x 8 - 12 x 14) = 168/5 minutes
? In 7 minutes 5/168 x 7 = 5/24 part of the tank will be filled
? Requied answer = 1 - 5/24 = 19/24 part
Correct Answer: 3111/19
Explanation:
Required answer = (25 x 40 x 30) / (40 x 30 + 25 x 30 - 25 x 40)
= 600 / 19 = 3111/19 minutes
Correct Answer: 6 minutes to empty
Explanation:
Time taken to fill or empty the whole tank = (6 x 10) /(6 - 10) = - 15 minutes
- ve sign shows that the tank will be emptied.
? 2/5th full of the tank will be emptied in 15 x 2/5 = 6 minutes
Correct Answer: 8 min.
Explanation:
Let Y be closed after T min
Then, T x (1/ 24 + 1/32) + (18 - T) x 1/24 = 1
? (7 x T)/96 + (18 - T)/24 = 1
or 7T + 72 - 4T = 96.
? 3T = 24
or T = 8 min.
Correct Answer: 5760 litres
Explanation:
Part filled by inlet in 1 hour = (1/6 - 1/8) = 1/24
So, the inlet can fill the tank in 24 hours
? Capacity of the tank = Water that flows in 24 hours = (4 x 24 x 60) liters = 5760 liters
Correct Answer: 60 litres
Explanation:
Here w = 2 litres per hour
? Required answer = {(15 x 10) / (15 - 10)} x 2 = 60 litres.
Correct Answer: 120 min
Explanation:
Part filled by tap A in 1 min = 1/60
Let tap B fills the tank in x min
Then, Part filled by tap, B in 1 min = 1/x
According to the question,
1/60 + 1/x = 1/40
? 1/x = 1/40 - 1/60
&rArr ; 1/x = (3 - 2)/120
&rArr ; 1/x = 1/120
? Tap B can fill the tank in 120 min.
Correct Answer: 214/23 h
Explanation:
Part of tank filled by first tap in 1 h = 1/3
Part of tank filled by second tap in 1 h = 1/4
Part of tank emptied by third tap in 1 h = 1/5
Part of the tank filled by all pipes opened simultaneously in 1 h
= 1/3 + 1/4 - 1/5 = (20 + 15 - 12)/60 = 23/60
Time taken by all the taps to fill the tank when it is empty = 23/60 h = 214/23 h
Correct Answer: 93/13 h
Explanation:
Part filled by A in 1 min = 1/30
Part filled by B in 1 min = 1/10
Part emptied by C in 1 min = - 1/40
Net part filled in 1 h by ( A + B + C ) = ( 1/30 + 1/10 - 1/40 )
= (4 + 12 - 3)/120 = 13/120
? Required time to fill the tank = 120/13 = 93/13 h
Correct Answer: 40 h
Explanation:
Let the leak takes x h to empty the tank.
Now, part filled by inlet in 1 h = 1/8
part filled in 1 h when both tap and leak works together = 1/(8+2) = 1/10
According to the question.
1/x = 1/8 - 1/10 = (5 - 4) / 40 = 1/40
? x = 40 h
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