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A pipe can empty a tank in 40 Minutes , A second Pipe with diameter twice as much as that of the first pipe is also attached to the tank to empty it .The two pipes can together empty the tank is

From this question

I need to get data:

single pipe 40 Minutes

I have tried

for first pipe - 1/40

second pipe - 1/20

so

i have consider as tank volume as 1

1-(1/40 + 1/20)t =0

If i find t,i will get answer, is this approach is correct

How i need to approach this question and please anyone guide me for solving this question

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    Devoting increasing? can you tell the reason behind this – 2017-02-22

1 Answers 1

4

Hint:

A pipe with double the diameter will take half-time to fill the same tank. So, the second pipe can empty the full tank in $10$ min.

Hint 2:

The part emptied by both in one minute will be equal to $\frac {1}{40} + \frac {1}{10} = \frac {5}{40}$. The tank will thus be emptied in (?) minutes. Hope you can take it from here.

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    Is it t = 40/3 @Rohan – 2017-02-22
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    we are doing one Mistake , the area is proportional to the square of the diameter.so for second pipe is 1/40 *2*2 , time taken is 1/10, i think so @Rohan – 2017-02-22
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    @Learninguser Yes, thanks for pointing out the typo. As the volume of water emptied by the second pipe will be 4 times to that of first, the time taken will be 1/4 of that of the first pipe. – 2017-02-22