Formula

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Formula

by szDave » Thu Jan 24, 2013 7:14 am
Hello,

it seems really easy, and it is, but I don't get it :D


Image

So: isn't 9=3m, so m is 3 * 6=1/2m, then m is 12- answer is 36.

OA 27

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by GMATGuruNY » Thu Jan 24, 2013 7:56 am
For all positive integers m, @m=3m when m is odd and @m=(1/2)m when m is even. What does @9 x @6 equate to?

A - @81
B - @59
C - @36
D - @27
E - @18
Since @m=3m when m is odd, @9 = 3*9 = 27.

Since @m=(1/2)m when m is even, @6 = (1/2)6 = 3.

Thus, @9 * @6 = 27*3 = 81.

Notice the @ symbol in the answer choices.
The correct answer must be the EQUIVALENT of 81.

Answer choice D: @27
Since @m=3m when m is odd, @27 = 3*27 = 81.

The correct answer is D.

Answer choice A is A TRAP.
Always beware of an answer choice that seems TOO EASY or TOO OBVIOUS.
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