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-ve Series

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-ve Series

by manu.pant » Sun Feb 06, 2011 11:11 pm
A chemical plant has four tanks (A, B, C and D), each containing 1000 litres of a
chemical. The chemical is being pumped from one tank to another as follows:
From A to B @ 20 litres/minute From C to A @ 90 litres/minute From A to D @ 10
litres/minute From C to D @ 50 litres/minute From B to C @ 100 litres/minute
From D to B @ 110 litres/minute Which tank gets emptied first and how long does it
take (in minutes) to get empty after pumping starts?


Ans: C, 20
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by jaxis » Sun Feb 06, 2011 11:34 pm
manu.pant wrote:A chemical plant has four tanks (A, B, C and D), each containing 1000 litres of a
chemical. The chemical is being pumped from one tank to another as follows:
From A to B @ 20 litres/minute From C to A @ 90 litres/minute From A to D @ 10
litres/minute From C to D @ 50 litres/minute From B to C @ 100 litres/minute
From D to B @ 110 litres/minute Which tank gets emptied first and how long does it
take (in minutes) to get empty after pumping starts?


Ans: C, 20
Shouldnt it be D,20.
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by manu.pant » Mon Feb 07, 2011 12:11 am
Correction: D, 20
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by Anurag@Gurome » Mon Feb 07, 2011 12:13 am
manu.pant wrote:From A to B @ 20 L/min
From C to A @ 90 L/min
From A to D @ 10 L/min
From C to D @ 50 L/min
From B to C @ 100 L/min
From D to B @ 110 L/min
Let us determine the final IN(+) or OUT(-) rate for each of the tank,
  • For A : -20 (to B) + 90 (from C) - 10 (to D) = +60 L/min
    For B : +20 (From A) - 100 (to C) + 110 (from D) = +30 L/min
    For C : -90 (to A) - 50 (to D) + 100 (from B) = -40 L/min
    For D : +10 (from A) + 50 (from C) - 110 (to B) = -50 L/min
As D has the maximum outlet rate of 50L/min, it'll empty first.
It'll take (1000/50) = 20 min to empty.
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by manu.pant » Mon Feb 07, 2011 7:56 pm
how can we find the time taken thru -ve series??
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