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Positive integer y is 50 percent of 50 percent of positive [#permalink]
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02 Jul 2012, 01:05
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The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectPositive integer y is 50 percent of 50 percent of positive integer x, and y percent of x equals 100. What is the value of x? (A) 50 (B) 100 (C) 200 (D) 1,000 (E) 2,000 Diagnostic Test Question: 12 Page: 22 Difficulty: 650 GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide for GMAT® Review, 13th 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: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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02 Jul 2012, 01:05
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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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02 Jul 2012, 01:58
y = 50% of 50% 0f x = x/4 and
y/100 of x = 100
y /100 *4y =100 y = 50 and x= 200
Answer  C



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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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02 Jul 2012, 01:59
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Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectPositive integer y is 50 percent of 50 percent of positive integer x, and y percent of x equals 100. What is the value of x? (A) 50 (B) 100 (C) 200 (D) 1,000 (E) 2,000 Diagnostic Test Question: 12 Page: 22 Difficulty: 650 GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide for GMAT® Review, 13th 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! The first information can be rewritten as \(y=0.5*0.5x=0.25x=\frac{x}{4}\), while the second information can be translated into \(\frac{y}{100}x=100\). If we substitute y from the first equation into the second one, we get \(\frac{x}{400}x=100\), from which \(x^2=400*100\), or \(x=\sqr{400*100}=\sqr{400}*\sqr{100}=20*10=200\). Answer: C
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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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03 Jul 2012, 09:05
y=(1/2)*(1/2)*x =>x=4y (y/100)*x=100 => y^2=100*100/4 y=100/2=50 x=4*50=200
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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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03 Jul 2012, 10:43
Given that Y= (50%)*(50%)*X Y=(50/100)*(50/100)*X Y=(1/2)*(1/2)*X {1}
and also,
(Y%)*(X) = 100 (Y/100)*X = 100 Y=(100*100)/X
from {1}
(1/2)*(1/2)*X = (100 *100)/X X^2 = 2*2*100*100
so, X=200.



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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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09 Jul 2012, 18:36
I think this is a 300500 level problem
are you sure it is a 650 level .. doubt it



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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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11 Jul 2012, 00:04



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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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25 Jul 2012, 09:21
looks to be lesser than 600 question. Just manipulation with what is given.
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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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30 Jun 2015, 02:45
I need help understanding a pretty basic bit of substitution in the first explanation (I'm tired!). How do you jump from xy = 100 x 100 to x^2 = 4 x 100 x 100?
Thanks



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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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30 Jun 2015, 02:50



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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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30 Jun 2015, 04:14
BunuelAh, of course, I must be having one of those days! thanks



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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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03 Sep 2017, 21:59
y=0.25x yx = 10000 substituting y 10000/x = 0.25 x 400 00 = x^2 then x = 200
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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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11 Sep 2017, 03:42
Easy way. Use answer choice and start from the middle. Let x=200 50% of X=100 50% of 100=50 y=50 Now y(50%) of x(200)=100



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Re: Positive integer y is 50 percent of 50 percent of positive [#permalink]
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14 Sep 2017, 09:37
Bunuel wrote: Positive integer y is 50 percent of 50 percent of positive integer x, and y percent of x equals 100. What is the value of x?
(A) 50 (B) 100 (C) 200 (D) 1,000 (E) 2,000
We can create the following equations: y = (0.5)(0.5)x y = 0.25x and (y/100)x = 100 Substitute y = 0.25x into the above equation: (0.25x/100)x = 100 0.25x^2 = 10,000 x^2 = 40,000 x = 200 Answer: C
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