Probabilit

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Probabilit

by [email protected] » Sat Dec 21, 2013 8:33 pm
Request you to explain in detail the concept!
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by Patrick_GMATFix » Sat Dec 21, 2013 8:57 pm
The two solutions below are taken from the GMATFix App.

Solution A
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Solution B
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by Stuart@KaplanGMAT » Sun Dec 22, 2013 1:37 am
Hi!

This may look like a probability question, but it's really all about geometry. The question is really asking "what portion of ABCD is shaded?"

This question is super quick if you use your graph-lined noteboard to draw the shape to scale - you'll quickly see that the mini square in the bottom right is 1/16 of the entire shape and that the shaded region is identical to 3 of that mini square, so it comprises 3/16 of the big square.

No more work required, 3/16 is the correct answer.

What are the big takeaways from this question?

1) Redraw shapes on your noteboard, especially when they're not to scale.

2) The more complicated the question, the more time you need to spend deconstructing it. If you start doing calculations without understanding what the question is asking, you're just wasting time!

Stuart
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by GMATGuruNY » Sun Dec 22, 2013 4:32 am
[email protected] wrote:Request you to explain in detail the concept!
As Stuart has wisely suggested, REDRAW the figure on your grid-covered noteboard so that AE=ED:

Image

ABCD is composed of 16 little squares.
Of these 16 squares, 3 make up the shaded region.
P(x will be in the shaded region) = 3/16.

The correct answer is D.
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