GRE Mixing Tank and Flow

[bartonij]

64 Gallon drum. Stream A is flowing in at 2 Gal/hour and Stream B is flowing out at X Gal/hour. What rate must stream B flow to have the tank full at 96 hours?

Thank You.

[sporty.arjun]

let speed of B be x
64=96(2)-96(x)
on solving x=4/3 gal/hr...

[Harsh Gupta]

Is the answer 1.33?

[prithibi]

i've got 1.33 ga/hr too.

[julle286]

First, calculate how long it takes to fill the drum.

2 Gallons * 32 Hours = 64 Gallons ; it takes 32 Hours.

Now, calculate the "required stream" when it takes 96 Hours:

x Gallons * 96 Hours = 64 Gallons.

X = 2/3 .



If the stream is 2 / 3 Gallons per Hour, the drum well be full in 96 Hours.

But as Flow a is 2 Gallons per Hour: 2 - 2/3 = 4/3

[w00t.cricket]

Good question this :

My way of looking at this problem:

The Drum would be full in 96 Hours .. (part of question)
So Inlet A would fill up how many gallons in that 96 hours? ==> 2* 96 = 192 Gallons
At the same time Outlet A would take away how many gallons? ==> x* 96 = 96x Gallons

So at this point the drum was full ie. ===> 64 Gallons

So following equation holds good :
192 - 96x = 64

Therefore x = 4/3 ..