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Sub 505 (Easy)|   Work and Rate Problems|                              
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Pumping alone at their respective constant rates, one inlet pipe fills 29 Apr 2021, 00:35
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Solution:

First pipe - Fills 1/2 tank in 3 hours =>1 full tank in 6 hours

Second pipe- Fills 2/3 rd tank in 6 hours = > 1 full tank in 6 * (3/2) = 9 hours

LCM(6,9) = 18 => Let the capacity of the tank be 18 units

=> Efficiency of first pipe = 18/6 = 3 units/hour

=>Efficiency of second pipe = 18/9 = 2 units/hour

Working together, they fill 3+2 =5 units/hour

=> They would take 18/5 = 3.6 hours (option b)

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Pumping alone at their respective constant rates, one inlet pipe fills 12 May 2021, 00:53
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rite2deepti
Pumping alone at their respective constant rates, one inlet pipe fills an empty tank to 1/2 of capacity in 3 hours and a second inlet pipe fills the same empty tank to 2/3 of capacity in 6 hours. How many hours will it take both pipes, pumping simultaneously at their respective constant rates, to fill the empty tank to capacity?

A. 3.25
B. 3.6
C. 4.2
D. 4.4
E. 5.5
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Answer: Option B

Video solution by GMATinsight

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Pumping alone at their respective constant rates, one inlet pipe fills 13 May 2021, 07:17
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rate of pipe 1 ; 1/2 capacity in 3 hours so in 6 hours 1 unit
and rate of pipe 2 ; 2/3 in 6 hrs ; if capacity if 3 so per unit 3 hrs and full will be 9 hours
combined rate ; 1/6+1/9 ; 54/15 ; 3.6
option B


rite2deepti
Pumping alone at their respective constant rates, one inlet pipe fills an empty tank to 1/2 of capacity in 3 hours and a second inlet pipe fills the same empty tank to 2/3 of capacity in 6 hours. How many hours will it take both pipes, pumping simultaneously at their respective constant rates, to fill the empty tank to capacity?

A. 3.25
B. 3.6
C. 4.2
D. 4.4
E. 5.5
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Pumping alone at their respective constant rates, one inlet pipe fills 08 Apr 2023, 15:00
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Pumping alone at their respective constant rates, one inlet pipe fills an empty tank to 1/2 of capacity in 3 hours and a second inlet pipe fills the same empty tank to 2/3 of capacity in 6 hours. How many hours will it take both pipes, pumping simultaneously at their respective constant rates, to fill the empty tank to capacity?
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Pumping alone at their respective constant rates, one inlet pipe fills 15 Apr 2023, 23:52
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Let r1 be the rate at which the first inlet pipe fills the tank, and let r2 be the rate at which the second inlet pipe fills the tank. Then we can set up the following system of equations:

r1 * 3 = 1/2 (since the first inlet pipe fills the tank to half capacity in 3 hours)
r2 * 6 = 2/3 (since the second inlet pipe fills the tank to two-thirds capacity in 6 hours)
(r1 + r2) * t = 1 (since both pipes, pumping simultaneously at their respective constant rates, fill the tank to capacity in t hours)
Solving the first equation for r1 and the second equation for r2 gives:

r1 = 1/6
r2 = 1/9
Substituting these values into the third equation gives:

(1/6 + 1/9) * t = 1
Simplifying gives:
5/18 * t = 1
t = 18/5
t = 3.6 hours
Therefore, it will take both pipes, pumping simultaneously at their respective constant rates, 3.6 hours to fill the empty tank to capacity. The answer is (B).
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Pumping alone at their respective constant rates, one inlet pipe fills 19 Jul 2025, 23:32
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