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# Three hoses, x, y, and z, each pump water at a constant rate into a 70

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Math Expert
Joined: 02 Sep 2009
Posts: 58417
Three hoses, x, y, and z, each pump water at a constant rate into a 70  [#permalink]

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16 Jan 2017, 09:36
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Question Stats:

89% (00:57) correct 11% (01:24) wrong based on 161 sessions

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Three hoses, x, y, and z, each pump water at a constant rate into a 70,000-gallon tank. How long will it take the hoses to fill the tank up to the 30,000-gallon mark?

(1) The 3 hoses working simultaneously can fill half the tank in 5 hours.
(2) Hose y pumps water at half the rate of x.

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Intern
Joined: 26 Oct 2016
Posts: 5
Re: Three hoses, x, y, and z, each pump water at a constant rate into a 70  [#permalink]

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16 Jan 2017, 15:58
I say A.

From A you can derive that the total time is 10 hours because the rates are constant. Since W=R*T, we can figure out that the hoses work at a rate of 7000 gallons per hour. From there, you can figure out the time to get to 30000 gallons (but shouldn't go all the way - save time on the actual test). We don't need to worry about the individual rates so long as we know the combined rate, which we do here.

B only tells you about hoses X and Y, doesn't mention anything about Z. That won't work.
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Joined: 26 Mar 2013
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Re: Three hoses, x, y, and z, each pump water at a constant rate into a 70  [#permalink]

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17 Jan 2017, 15:58
1
1
Three hoses, x, y, and z, each pump water at a constant rate into a 70,000-gallon tank. How long will it take the hoses to fill the tank up to the 30,000-gallon mark?

(1) The 3 hoses working simultaneously can fill half the tank in 5 hours.

3 hoses takes 10 hrs to fill out the whole tank. It means to we can fill 30000/70000=3/7 in (3/7*10= 4 2/7) hrs

Sufficient

(2) Hose y pumps water at half the rate of x.

No info about z. Insufficient

Answer: A
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Joined: 24 Jul 2016
Posts: 50
Re: Three hoses, x, y, and z, each pump water at a constant rate into a 70  [#permalink]

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14 Jul 2017, 01:20
Bunuel wrote:
Three hoses, x, y, and z, each pump water at a constant rate into a 70,000-gallon tank. How long will it take the hoses to fill the tank up to the 30,000-gallon mark?

(1) The 3 hoses working simultaneously can fill half the tank in 5 hours.
(2) Hose y pumps water at half the rate of x.

i think the qn should have mentioned all the hoses running simultaneously.
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Joined: 03 Jul 2017
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Concentration: Finance, International Business
Re: Three hoses, x, y, and z, each pump water at a constant rate into a 70  [#permalink]

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07 Aug 2017, 23:52
If the time take to fill half of the tank is 5 hours, that means to fill 35000 gallons its going to take 5 hours. Therefore to fill 30000 gallons , we can find the time by cross multiplying. So sufficient

Statement 2 tells us only about the rate of y and x . So therefore NS.
Answer is A
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Re: Three hoses, x, y, and z, each pump water at a constant rate into a 70  [#permalink]

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06 Mar 2019, 10:36
Answer should be E since there should be communication before filling is it empty or somewhat filled?
Re: Three hoses, x, y, and z, each pump water at a constant rate into a 70   [#permalink] 06 Mar 2019, 10:36
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# Three hoses, x, y, and z, each pump water at a constant rate into a 70

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