This set of Aptitude Questions and Answers (MCQs) focuses on “Two Pipes – Set 2”.
1. 2 pipes can fill a tank in 5 minutes and 12.5 minutes, respectively. What is the time required to fill the tank using the second pipe if the first pipe is opened for 2 minutes?
a) 5 minutes
b) 7.5 minutes
c) 9.5 minutes
d) 10 minutes
View Answer
Explanation: Let the capacity of the tank be 25 liters.
The efficiency of the pipes = 25 / 5, 25 / 12.5 = 5, 2
The first pipe is opened for 2 minutes = 10 liters of water flowed through first pipe
The amount of water left to be filled = 25 – 10 = 15 liters
The time required to fill the remaining water by second pipe = 15 / 2 = 7.5 minutes
2. 2 pipes can fill a tank in 5 minutes together. If the efficiency of first pipe is 4 times the efficiency of second pipe, find the time required to fill the tank using the second pipe.
a) 8 minutes
b) 16 minutes
c) 20 minutes
d) 25 minutes
View Answer
Explanation: Let the efficiency of the second pipe be x.
The efficiency of the first pipe = 4 * x = 4x
The total efficiency = x + 4x = 5x
The time required = 5 minutes
The total capacity = 5 * 5x = 25x
The time required to fill the tank using the second pipe = 25x / x = 25 minutes
3. 2 pipes can fill a tank in 8 minutes when opened together. If the first pipe can fill the tank in 32 minutes find the time required by the second pipe to fill the tank.
a) 540 seconds
b) 640 seconds
c) 940 seconds
d) 1040 seconds
View Answer
Explanation: Let the tank be 32 liters in capacity.
The efficiency of the first pipe = 32 / 32 = 1
The efficiency of the pipes together = 32 / 8 = 4
The efficiency of the second pipe = 4 – 1 = 3
The time required by the second pipe to fill the tank = 32 / 3 = 10.66 minutes or 640 seconds
4. 2 pipes can fill a tank in 9 minutes when opened simultaneously. If the efficiency of the first pipe is twice the efficiency of the second pipe, find the time required by the second pipe to fill the tank.
a) 9 minutes
b) 3 minutes
c) 27 minutes
d) 15 minutes
View Answer
Explanation: let the capacity of the tank be 9 liters.
Let the efficiency of the second pipe be x.
The efficiency of the first pipe = x * 2 = 2x
The total relative efficiency = 3x
The time required = 9 minutes
9 / 3x = 9
X = 1 / 3
The time required by the second pipe to fill the tank = 9 / x = 9 / 1 / 3 = 9 * 3 = 27 minutes
5. 2 pipes have an efficiency of x and 7x, respectively. If combined they can fill a tank in 5096 seconds, how long will it take to fill the tank using only the second pipe?
a) 1 hour 34 minutes and 7 seconds
b) 1 hour 43 minutes and 7 seconds
c) 1 hour 37 minutes and 4 seconds
d) 1 hour 37 minutes and 2 seconds
View Answer
Explanation: The combined relative efficiency = x + 7x = 8x
The time required to fill the tank with 8x efficiency = 5096 seconds
The time required to fill the tank with 7x efficiency = 5096 * 8x / 7x = 5824 seconds
5824 seconds in minutes = 97 minutes and 4 seconds = 1 hour 37 minutes and 4 seconds
6. 2 pipes can fill a tank in 4 minutes and 5 minutes, respectively. How long will it take to fill 90% of the tank using both the pipes together?
a) 108 seconds
b) 112 seconds
c) 120 seconds
d) 126 seconds
View Answer
Explanation: Let the capacity of the tank be 20 liters.
The efficiency of the pipes = 20 / 4, 20 / 5 = 5, 4
The combined efficiency = 9
The amount of water to be filled = 20 * 90 / 100 = 18 liters
The time required = 18 / 9 = 2 minutes = 2 * 60 = 120 seconds
7. 2 pipes can fill a tank in 8 seconds and 1 minute, respectively. Find the time required to fill the tank when the second pipe is already opened 20 seconds prior to the first pipe.
a) 4 seconds
b) 4.2 seconds
c) 4.5 seconds
d) 4.7 seconds
View Answer
Explanation: Let the capacity of the tank be 60 liters.
The efficiency of the first pipe = 60 / 8 = 7.5
The efficiency of the second pipe = 60 / 60 = 1
The second pipe is opened for 20 seconds = 20 liters of water filled already
The amount of water left = 60 – 20 = 40 liters
The time required = 40 / 8.5 = 4.7 seconds
8. 2 pipes have an efficiency of 3x and 12x, respectively. If together they can fill a tank of 13500 liters in capacity in 3 hours, find the time required to fill 4 such tanks using the second pipe only.
a) 9 hours
b) 12 hours
c) 15 hours
d) 18 hours
View Answer
Explanation: The combined efficiency = 3x + 12x = 15x
The total amount of water to be filled = 13500 * 4 = 54000 liters
The time required by both the pipes together to fill a tank of 13500 liters = 3 hours = 180 minutes
13500 / 15x = 180 minutes
X = 900 / x = 180
X = 5
The efficiency of the second pipe = 12x = 60
Time required to fill 54000 liters = 54000 / 60 = 900 minutes = 15 hours
9. 2 pipes can fill a tank in 7 minutes and 3 minutes, respectively. Find the time required in seconds to fill the tank if both the pipes are opened simultaneously.
a) 120 seconds
b) 126 seconds
c) 132 seconds
d) 138 seconds
View Answer
Explanation: Let the capacity of the tank be 21 liters.
The efficiency of the pipes = 3 and 7, respectively.
The combined efficiency = 10
The time required to fill the tank = 21 / 10 = 2.1 minutes = 2.1 * 60 = 126 seconds
10. 2 pipes can fill a tank in 9 minutes and 290 seconds, respectively. Find the time in minutes required to fill the tank if both the pipes are opened simultaneously.
a) 3.14 minutes
b) 3.23 minutes
c) 3.34 minutes
d) 3. 41 minutes
View Answer
Explanation: Let the capacity of the tank be 15660 liters.
The efficiency of the pipes = 15660 / 540, 15660 / 290 = 29 and 54 respectively
The total relative efficiency = 54 + 29 = 83
The time required in minutes = 15660 / (83 * 60) = 3.14 minutes
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