Pipe A and Pipe B together can fill the tank in 60 min

Question

Pipe A and Pipe B together can fill the tank in 60 min. Efficiency of Pipe A , B and C are in the ratio of 2 : 3 : 1. Pipe A and Pipe B are the inlet pipes whereas Pipe C is the outlet pipe. Find out the time taken by A and C together to fill the tank?
(a) 240 min
(b) 280 min
(c) 300 min
(d) 320 min
(e) 360 min

Abhishek009 · Accepted Answer

A and B fills up the tank in 60 mins so, capacity of the tank is 60*(2+3) = 300 units...

Combined efficiency of A - C = 1 Units/Hr

So, Time required to fill up the tank will be 300/1 = 300 Min, Answer must be (C)

TestPrepUnlimited · Answer

Hi  Swarna6387  , the key here is the rate of C is negative but I'll break it down step by step first.

Let us set the variables A, B, C as the respective rates. From the first sentence, we can get A and B have a combined rate of 1/60 (job per minute). Hence A + B = 1/60. 
We also know A:B = 2:3, we can solve for A and B this way: split the total into 5 equivalents, then A has two pieces and B has three pieces among the five. 
 \frac{1}{60}/5 = 1/300 .
 A = 1/300 * 2 = 1/150

Next, C is mentioned as an outlet pipe. This means C is working against A and B, and C has a negative rate. The magnitude of the rate of C is half of A, so C = -1/300. 
Finally, the combined rate of A and C is  A + C = 1/150 - 1/300 = 1/300 . Therefore it takes 300 minutes to fill the tank.

Ans: C

GMATBusters · Answer

Efficiency of Pipe A , B and C are in the ratio of 2 : 3 : 1
Hence, Let us suppose the work done per min by A , B and C are 2units, 3 units, 1 unit 
Pipe A and Pipe B together can fill the tank in 60 min
Hence total work = 60(2+3)= 500

When A and C are working together, net work done per min = 2-1= 1unit
time taken = (total work)/(work per min) = 300/1 = 300

Answer = C

Fdambro294 · Answer

(1st) Find the actual Rate of A

The Ratio of Efficiency between A - to - B = 2 : 3

When they work together, they take 60 minute to complete the job at their respective rates.

This means:

A will complete 2/5 of job——————> 60 minutes

*(5/2)
___________

A will complete 2/5 * (5/2) = 1 job in ————-> 60 * (5/2) = 150 minutes

Doing the same thing for B using the Unitary Method, you find that B can do the 1 job in 100 minutes

A: can do 1 job in 150 min

B: can do 1 job in 100 min

(2nd) since the Ratio of Efficiency Rates between A -to- C = 2 : 1

This means that A can do TWICE the work in the same time that C can.

If it takes A 150 minute to do the 1 job, it will take C TWICE as long on its own to do the 1 job.

C can do 1 job in 300 minutes.

(3rd)Solve

Rate of A = (1 / 150) job per min.

Rate of C = (1 / 300) job per min.

Let T = the time it takes to fill the Job of 1 tank while A is pumping water IN and C is draining water OUT

(1/150)T - (1/300)T = 1 job

T/150 - T/300 = 1

(2T - T) / 300 = 1

T = 300 minutes

(C)

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GmatPoint · Answer

Let the efficiency of pipes A, B, and C per minute be 2x, 3x, and x, respectively.

Since A and B are inlet pipes and can fill the tank in 60 minutes,
Capacity of the tank = 60(2x + 3x) = 300x

Total work done by A and C together in 1 minute = 2x - x = x

Thus, the total time taken by A and C to complete the work = 300x/x = 300 min.

Thus, the correct option is C.

ThatDudeKnows · Answer

Let's give ourselves units and just Plug In! I'll go with gallons.

A fills at a rate of 2 gallons per minute. In 60 minutes, A fills 120 gallons.
B fills at a rate of 3 gallons per minute. In 60 minutes, B fills 180 gallons.
That fills the tank, so the tank is 300 gallons.

How long will it take A and C together? 
A is filling at a rate of 2 gallons per minute and C is releasing 1 gallon per minute.
We are gaining 1 gallon per minute in net.
It will take 300 minutes.

Answer choice C.

ashishpathak · Answer

A and B together fill the tank in 60 mins .Let the volume of the tank be 60 units so as per the ratio given between A and B .A has filled 24 units and B has filled 36 units in one hour.
Now the ratio of A: C is 2:1 therefore if A is 24 units per hour C will be 12 unitsper hour.
With A and C working in tandem every hour: 24 units in by A and 12 units out by B in,giving a net input of 12 units per hour.(A+B)
Also total time required to fill the tank will be 60/12 = 5 hours or 300 mins (C)

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bumpbot · Answer

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Pipe A and Pipe B together can fill the tank in 60 min

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Pipe A and Pipe B together can fill the tank in 60 min

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