A group of x people is practicing levitation yoga. One-fourt

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Economist GMAT

A group of x people is practicing levitation yoga. One-fourth of the people rise up in the air, and after a while, 3 of them come back down. How many people are now practicing yoga on the ground?

A. 2/3*(x+3)
B. (3/4)(x+4)
C. 3(4x+4)
D. 3(x+4)
E. 4(3x+4)

OA B

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by Brent@GMATPrepNow » Thu Feb 14, 2019 10:04 am
AAPL wrote:Economist GMAT

A group of x people is practicing levitation yoga. One-fourth of the people rise up in the air, and after a while, 3 of them come back down. How many people are now practicing yoga on the ground?

A. 2/3*(x+3)
B. (3/4)(x+4)
C. 3(4x+4)
D. 3(x+4)
E. 4(3x+4)
One-fourth of the people rise up in the air
If 1/4 of the x people are in the AIR, the remaining 3/4 of the x people are on the GROUND
So, (3/4)x = number of people on the GROUND

After a while, 3 of them come back down.
So, the number of people on the GROUND is increased by 3

So, now (3/4)x + 3 = number of people on the GROUND

Check the answer choices . . . not there!
Or so it seems.

If we take answer choice B, (3/4)(x+4), and expand it, we get: (3/4)x + 3
PERFECT!

Answer: B

Cheers,
Brent
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by GMATGuruNY » Thu Feb 14, 2019 10:10 am
AAPL wrote:Economist GMAT

A group of x people is practicing levitation yoga. One-fourth of the people rise up in the air, and after a while, 3 of them come back down. How many people are now practicing yoga on the ground?

A. 2/3*(x+3)
B. (3/4)(x+4)
C. 3(4x+4)
D. 3(x+4)
E. 4(3x+4)
Let x=12.
Since 1/4 of the people rise up, the number who rise up = (1/4)(12) = 3.
Since 3 people come back down, EVERYONE who rises up comes back down, with the result that all 12 people are practicing yoga on the ground.

How many people are now practicing yoga on the ground?
The correct answer must yield 12 when x=12.
Only B works:
(3/4)(12+4) = (3/4)(16) = 3*4 = 12.

The correct answer is B.
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