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# If there are x men and y women in a choir, and there are z more men

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Manager
Joined: 20 Jan 2014
Posts: 142
Location: India
Concentration: Technology, Marketing
If there are x men and y women in a choir, and there are z more men  [#permalink]

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Updated on: 03 Oct 2014, 06:24
5
3
00:00

Difficulty:

35% (medium)

Question Stats:

69% (01:39) correct 31% (02:13) wrong based on 302 sessions

### HideShow timer Statistics

If there are x men and y women in a choir, and there are z more men than there are women in that choir, what is z?

(1) x^2 – 2xy + y^2 – 9 = 0

(2) x^2 + 2xy + y^2 – 225 = 0

_________________

Originally posted by him1985 on 03 Oct 2014, 03:37.
Last edited by Bunuel on 03 Oct 2014, 06:24, edited 1 time in total.
Edited the question
Manager
Joined: 22 Jan 2014
Posts: 174
WE: Project Management (Computer Hardware)
Re: If there are x men and y women in a choir, and there are z more men  [#permalink]

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03 Oct 2014, 04:49
1
him1985 wrote:
I tried to search this question but did not found. If this question has already been posted then please point me in right direction. Thanks

Ques: If there are x men and y women in a choir, and there are z more men than there are women in that choir, what is z?

(1) x2 – 2xy + y2 – 9 = 0

(2) x2 + 2xy + y2 – 225 = 0

A.

we know, x = y+z

1) (x-y)^2 = 3^2
or (x-y) = 3
x = y+3
so z=3

2) (x+y)^2 = 15^2
or x+y=15
insufficient.
_________________

Illegitimi non carborundum.

Manager
Joined: 27 Jan 2015
Posts: 126
Concentration: General Management, Entrepreneurship
GMAT 1: 670 Q44 V38
Re: If there are x men and y women in a choir, and there are z more men  [#permalink]

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26 Apr 2015, 17:48
Is there an easier way to solve this question? When I see long equations I get so intimidated and I am terrible at factoring. Like every question that requires factoring makes me cringe. The numbers never come naturally to me and I usually blindly guess until too much time has passed and I have to guess the answer anyways!
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Re: If there are x men and y women in a choir, and there are z more men  [#permalink]

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27 Apr 2015, 14:26
3
Hi sabineodf,

Many Quant questions on Test Day are pattern-based, so instead of looking at a prompt and thinking "what is this?", try thinking "what does this REMIND ME of?" In that way, you'll probably be less intimidated by the structure of the questions.

The prompt is worded in a 'quirky' way, but the information isn't that complex. From the two Facts, you should recognize that we're meant to be thinking about Classic Quadratics. If you're familiar with the 3 Classic Quadratics, then the bulk of the work in this question is just about re-writing information (and not about hard-core math skills).

For example, you are expected to know that....

X^2 -2XY + Y^2 can be re-written as....

(X-Y)(X-Y) =

(X-Y)^2

If you're not familiar enough with those ideas/rules yet, then that's okay, but you DO have to have to become familiar and practice them. Algebra is a BIG category in the Quant section, so you have to make sure that you're familiar enough with the broad concepts (and can do the specific calculations when required).

GMAT assassins aren't born, they're made,
Rich
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Manager
Joined: 27 Jan 2015
Posts: 126
Concentration: General Management, Entrepreneurship
GMAT 1: 670 Q44 V38
Re: If there are x men and y women in a choir, and there are z more men  [#permalink]

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27 Apr 2015, 17:02
Director
Joined: 12 Nov 2016
Posts: 725
Location: United States
Schools: Yale '18
GMAT 1: 650 Q43 V37
GRE 1: Q157 V158
GPA: 2.66
Re: If there are x men and y women in a choir, and there are z more men  [#permalink]

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10 Sep 2017, 12:52
him1985 wrote:
If there are x men and y women in a choir, and there are z more men than there are women in that choir, what is z?

(1) x^2 – 2xy + y^2 – 9 = 0

(2) x^2 + 2xy + y^2 – 225 = 0

This question is just testing quadratic templates

St 1

(x-y)(x-y) =9

Since this question is basically asking for the difference between a certain amount of people the answer can't necessarily be negative so x-y =2

suff

St 2

(x +y)(x+y) =225

insuff

A
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Re: If there are x men and y women in a choir, and there are z more men  [#permalink]

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07 Oct 2018, 09:25
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: If there are x men and y women in a choir, and there are z more men   [#permalink] 07 Oct 2018, 09:25
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