Set problem

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Set problem

by Joy Shaha » Wed Jan 11, 2017 7:18 am
Q. Of 30 applicants for a job , 14 at least 4 years' experience ;18 had degrees and 3 had less than 4 years' experience and don't have a degree. How many of the applicants had at least 4 years' experience and a degree ?
A.14;
B.13
C.9 ;
D.7 ;
E.5

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by Brent@GMATPrepNow » Wed Jan 11, 2017 7:27 am
There's a very thorough discussion (with several different approaches) of that question here: https://www.beatthegmat.com/job-applican ... 74450.html

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by [email protected] » Wed Jan 11, 2017 10:39 am
Hi Joy Shaha,

There are a number of different ways to approach this question. Here's one that uses the Tic-Tac-Toe board.

The initial 3x3 grid contains the information given by the prompt.

The second 3x3 grid contains the first set of deductions (the sub-totals, in blue), followed by the sub-groups (in green).

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The answer to the question is in the upper-left corner: E

GMAT assassins aren't born, they're made,
Rich
Last edited by [email protected] on Wed Jan 11, 2017 11:11 am, edited 1 time in total.
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by regor60 » Wed Jan 11, 2017 11:09 am
[email protected] wrote:Hi Joy Shaha,

There are a number of different ways to approach this question. Here's one that uses the Tic-Tac-Toe board.

The initial 3x3 grid contains the information given by the prompt.

The second 3x3 grid contains the first set of deductions (the sub-totals, in blue), followed by the sub-groups (in green).

Image

The answer to the question is in the upper-left corner: A

GMAT assassins aren't born, they're made,
Rich

The answer is in fact not A. It is E

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by [email protected] » Wed Jan 11, 2017 11:12 am
Hi regor60,

Thanks for catching the typo. I've amended the post.

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by Brent@GMATPrepNow » Wed Jan 11, 2017 11:18 am
I thought I'd point out that Rich's "Tic-Tac-Toe" approach goes by many names, including the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it.

Here, we have a population of applicants , and the two characteristics are:
- least 4 years of experience or not least 4 years of experience
- has degree or doesn't have a degree

This question type is VERY COMMON on the GMAT, so be sure to master the technique.

To learn more about the Double Matrix Method, watch this video: https://www.gmatprepnow.com/module/gmat- ... ems?id=919

Once you're familiar with this technique, you can attempt these additional practice questions:

Easy Problem Solving questions
- https://www.beatthegmat.com/finance-majo ... 67425.html

Medium Problem Solving questions
- https://www.gmatprepnow.com/module/gmat- ... /video/920
- https://www.beatthegmat.com/posted-speed ... 72374.html
- https://www.beatthegmat.com/motel-t271938.html
- https://www.beatthegmat.com/of-the-appli ... 70255.html
- https://www.beatthegmat.com/opening-nigh ... 64869.html
- https://www.beatthegmat.com/at-least-100 ... 74669.html
- https://www.beatthegmat.com/prblem-solving-t279424.html

Difficult Problem Solving questions
- https://www.gmatprepnow.com/module/gmat- ... /video/946
- https://www.beatthegmat.com/ratio-problem-t268339.html
- https://www.beatthegmat.com/overlapping- ... 65223.html
- https://www.beatthegmat.com/fractions-t264254.html
- https://www.beatthegmat.com/overlapping- ... 64092.html
- https://www.beatthegmat.com/mba/2011/05/ ... question-2

Easy Data Sufficiency questions
- https://www.gmatprepnow.com/module/gmat- ... /video/943
- https://www.beatthegmat.com/for-what-per ... 70596.html
- https://www.beatthegmat.com/ds-quest-t187706.html

Medium Data Sufficiency questions
- https://www.beatthegmat.com/sets-matrix-ds-t271914.html
- https://www.beatthegmat.com/each-of-peop ... 71375.html
- https://www.beatthegmat.com/a-manufacturer-t270331.html
- https://www.beatthegmat.com/in-costume-f ... 69355.html
- https://www.beatthegmat.com/mba/2011/05/ ... question-1

Difficult Data Sufficiency questions
- https://youtu.be/dsCeqF9Kbk8
- https://www.beatthegmat.com/double-set-m ... 71423.html
- https://youtu.be/dOZ9KM1m5Hs
- https://www.beatthegmat.com/sets-t269449.html
- https://www.beatthegmat.com/mba/2011/05/ ... question-3

Cheers,
Brent
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by Matt@VeritasPrep » Thu Jan 19, 2017 9:22 pm
You can also always turn to algebra:

Total = 30
4+ years = 14
Degrees = 18
Neither = 3

Total - Neither = (4+ Years) + (Degrees) - Both

30 - 3 = 14 + 18 - Both

Both = 5

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by Jeff@TargetTestPrep » Tue Jan 23, 2018 9:20 am
Joy Shaha wrote:Q. Of 30 applicants for a job , 14 at least 4 years' experience ;18 had degrees and 3 had less than 4 years' experience and don't have a degree. How many of the applicants had at least 4 years' experience and a degree ?
A.14;
B.13
C.9 ;
D.7 ;
E.5
We can use the equation:

Total = At least 4 years of experience + Degrees - Both + Neither

30 = 14 + 18 - B + 3

30 = 35 - B

B = 5

Answer: E

Jeffrey Miller
Head of GMAT Instruction
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