For all positive integers $$m, [m] = 3m$$ when $$m$$ is odd and $$[m] = \dfrac{m}2$$ when $$m$$ is even. What is

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For all positive integers $$m, [m] = 3m$$ when $$m$$ is odd and $$[m] = \dfrac{m}2$$ when $$m$$ is even. What is

by Vincen » Thu Jun 10, 2021 11:33 am

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For all positive integers $$m, [m] = 3m$$ when $$m$$ is odd and $$[m] = \dfrac{m}2$$ when $$m$$ is even. What is $$[9]\cdot [6]$$ equivalent to?

A. $$[81]$$

B. $$[54]$$

C. $$[37]$$

D. $$[27]$$

E. $$[18]$$

Source: GMAT Prep

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Re: For all positive integers $$m, [m] = 3m$$ when $$m$$ is odd and $$[m] = \dfrac{m}2$$ when $$m$$ is even. What is

by [email protected] » Fri Jun 11, 2021 6:41 am
Vincen wrote:
Thu Jun 10, 2021 11:33 am
For all positive integers $$m, [m] = 3m$$ when $$m$$ is odd and $$[m] = \dfrac{m}2$$ when $$m$$ is even. What is $$[9]\cdot [6]$$ equivalent to?

A. $$[81]$$

B. $$[54]$$

C. $$[37]$$

D. $$[27]$$

E. $$[18]$$

Source: GMAT Prep
9 is odd, so [9] = (3)(9) = 27
6 is even, so [6] = 6/2 = 3
So, [9] x [6] = 27 x 3 = 81

BEFORE you select answer choice A, notice that 81 has brackets around it.
Since 81 is odd, [81] = (3)(81) = 243
So, answer choice A is NOT correct.

So, which of the 5 answer choices equals 81?

Since 27 is odd, [27] = (3)(27) = 81

So, the correct answer is D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com

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