Pipes and Cisterns Quiz Set 005

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Question 1

A tap can fill a tank in 2 hours. Because of a leak it took $2{3/8}$ hours to fill the tank. When the tank has been completely filled, the tap is closed. How long will the water last in the tank?

 A

$12{2/3}$ hrs.

 B

$20{1/2}$ hrs.

 C

$11{2/3}$ hrs.

 D

$9{2/5}$ hrs.

Soln.
Ans: a

Work done by the leak in one hour is $1/2 - 1/({19/8})$ = $1/2 - 8/19$ = $3/38$. So the leak will complete the whole task in ${38/3}$, which is same as: $12{2/3}$ hours.


Question 2

Three taps R, G and B are supplying red, green and blue colored inks into a tub. They can independently fill the tub in 6, 2 and 8 minutes. They are turned on at the same time. What is the ratio of blue ink after 3 minutes?

 A

${3/19}$.

 B

$1{2/9}$.

 C

${1/7}$.

 D

$2{6/7}$.

Soln.
Ans: a

Let the time taken by them to independently fill the tank be r, g and b minutes. Ink discharged by the blue tap is $3/b$. The total of all the inks is $3/r + 3/g + 3/b$. The ratio is ${1/b}/{1/r + 1/g + 1/b}$, which simplifies to ${rg}/{rg + gb + br}$ = ${3/19}$.


Question 3

Pipe A can fill a cistern in 105 minutes, while the pipe B can fill it in 70 minutes. They are alternately open for 1 minute. How long will it take the cistern to fill completely?

 A

84 mins.

 B

85 mins.

 C

83 mins.

 D

86 mins.

Soln.
Ans: a

Let the total time taken be 2x minutes. Both X and Y run for x mins. So $(x/70 + x/105)$ = 1. Solving for x, we get x = 42, which gives 2x = 84.


Question 4

One tap can fill a tank 4 times faster than the other. If they together fill it in 6 minutes, how much time does the slower alone take to fill the tank?

 A

30 mins.

 B

5 mins.

 C

3 mins.

 D

7 mins.

Soln.
Ans: a

Let the one minute work of the taps be 1/x and 4/x. We have $1/x + 4/x = 1/6$, which gives x = 5 × 6 = 30 mins.


Question 5

Two taps A and B can fill a tank in 16 and 32 minutes respectively. Both the taps are turned on at the same time. After how many minutes should B be turned off so that the tank can be filled in 12 minutes?

 A

8 mins.

 B

9 mins.

 C

7 mins.

 D

11 mins.

Soln.
Ans: a

Let B be closed after x mins. Then sum of works done by A and B = 1. $12/16 + x/32 = 1$. Solving, we get x = 8.


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This Blog Post/Article "Pipes and Cisterns Quiz Set 005" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2017-06-24.

Posted by Parveen(Hoven),
Aptitude Trainer


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