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After 4,000 gallons of water were added to a large water tan
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28 Jan 2014, 00:55
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The Official Guide For GMAT® Quantitative Review, 2ND EditionAfter 4,000 gallons of water were added to a large water tank that was already filled to 3/4 of its capacity, the tank was then at 4/5 of its capacity. How many gallons of water does the tank hold when filled to capacity? (A) 5,000 (B) 6,200 (C) 20,000 (D) 40,000 (E) 80,000 Problem Solving Question: 61 Category: Algebra Firstdegree equations Page: 69 Difficulty: 600 GMAT Club is introducing a new project: The Official Guide For GMAT® Quantitative Review, 2ND Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide For GMAT® Quantitative Review, 2ND Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution. We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation. Thank you!
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Re: After 4,000 gallons of water were added to a large water tan
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28 Jan 2014, 01:32
Initially the tank is 75% full. and 4000 gallons are added. then the tank becomes 4/5 or 80% full. so 5% is 4000. Then the 100% will be = \(4000 *100/5= 80,000\). Answer is E.
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Re: After 4,000 gallons of water were added to a large water tan
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28 Jan 2014, 00:55
SOLUTIONAfter 4,000 gallons of water were added to a large water tank that was already filled to 3/4 of its capacity, the tank was then at 4/5 of its capacity. How many gallons of water does the tank hold when filled to capacity?(A) 5,000 (B) 6,200 (C) 20,000 (D) 40,000 (E) 80,000 4,000 gallons of water comprise 4/5  3/4 = 1/20, which makes the capacity of the tank equal to 4,000*20 = 80,000 gallons. Answer: E.
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Re: After 4,000 gallons of water were added to a large water tan
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28 Jan 2014, 02:26
We can set up the following equation for the info in the question:
3/4 of x+4000=4/5 of x; where x is the capacity of the water tank.
x=80,000
Answer E
We can alternatively work this out using proportion: we know that the additional 4000 gallons account for 4/53/4=1/20 of the tank. So if 4000 gallons account for 1/20 of the full tank, then 20/20 of the tank is 80,000.
Still Answer E.



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Re: After 4,000 gallons of water were added to a large water tan
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28 Jan 2014, 07:54
1/20x=4000..x=80000..
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Re: After 4,000 gallons of water were added to a large water tan
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28 Jan 2014, 11:12
x=tank capacity
4000/x = (4/53/4)/1 4000 = 1/20(x) x=80000
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Re: After 4,000 gallons of water were added to a large water tan
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28 Jan 2014, 20:41
Let us assume the total capacity of tank to be x.
Since the tank was already filled to 3/4th(or 75%) of its capacity and 4,000 gallons of water were added to bring it to 4/5 th(or 80%) of its capacity, we can make the following inference: 5% of capacity(80%75%) = 4000; (5/100) * x = 4,000 x = 80,000;
Ans is (E).



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Re: After 4,000 gallons of water were added to a large water tan
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01 Feb 2014, 06:51
SOLUTIONAfter 4,000 gallons of water were added to a large water tank that was already filled to 3/4 of its capacity, the tank was then at 4/5 of its capacity. How many gallons of water does the tank hold when filled to capacity?(A) 5,000 (B) 6,200 (C) 20,000 (D) 40,000 (E) 80,000 4,000 gallons of water comprise 4/5  3/4 = 1/20, which makes the capacity of the tank equal to 4,000*20 = 80,000 gallons. Answer: E.
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Re: After 4,000 gallons of water were added to a large water tan
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02 Feb 2014, 05:48
After 4,000 gallons of water were added to a large water tank that was already filled to 3/4 of its capacity, the tank was then at 4/5 of its capacity. How many gallons of water does the tank hold when filled to capacity?
(A) 5,000 (B) 6,200 (C) 20,000 (D) 40,000 (E) 80,000
\(\frac{3}{4}\) of Tank = 75% of Tank
\(\frac{4}{5}\) of Tank = 80% of Tank
Given that, difference between 80% and 75% of Tank is 4000 gallons Or, 5% of Tank = 4000 gallons
Or, Full capacity of Tank \(= 20 * 4000 = 80000\) gallons of water
Answer: (E)



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Re: After 4,000 gallons of water were added to a large water tan
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11 Jul 2014, 00:07
Let full capacity of tank = x 3/4th of full capacity \(= \frac{3x}{4}\) Addition of 4000 gallons \(= \frac{3x}{4} + 4000\) Given that addition of water takes the level to 4/5th \(\frac{3x}{4} + 4000 = \frac{4x}{5}\) x = 4000 * 20 = 80000
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Re: After 4,000 gallons of water were added to a large water tan
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11 Jul 2014, 04:54
Let x be the capacity of tank
(4/5  3/4) x = 4000 (0.80.75)x = 4000 0.05 x = 4000 x = 4000 * 20 = 80,000



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Re: After 4,000 gallons of water were added to a large water tan
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29 Jul 2016, 11:00



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Re: After 4,000 gallons of water were added to a large water tan
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23 Sep 2018, 02:32
3/4*x+4000=4/5*x Solving for x, and getting x = 80K



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Re: After 4,000 gallons of water were added to a large water tan
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19 Oct 2018, 04:12
Let the currently existing water be x Total capacity be y
\(\frac{x}{y} = \frac{3}{4}\)
\(\frac{x+4000}{y} = \frac{4}{5}\)
\(\frac{x}{y} + \frac{4000}{y} = \frac{4}{5}\)
\(\frac{3}{4} + \frac{4000}{y} = \frac{4}{5}\)
\(\frac{4000}{y} = \frac{1}{20}\)
y = 80,000
Answer choice E




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