Question from GMATprep

[mbiasol]

I'm stuck with this question... it looks so easy but I can't solve it

For all positive integers m, [m] = 3m when m is odds and [m] = 1/2m when m is even
Which of the following is equivalent to [9]x[6]?

I answered 81...
[9] = 3*9 = 27
[6] = 6/2 = 3
27*3 = 81

The right answer is 27 .... The only way to obtain this value is to consider:
[9]x[6] = [81] = [3*m] => m = 27
By the way the question asks to give a value to [9]x[6] ...

[jnelson0612]

I'm stuck with this question... it looks so easy but I can't solve it

For all positive integers m, [m] = 3m when m is odds and [m] = 1/2m when m is even
Which of the following is equivalent to [9]x[6]?

I answered 81...
[9] = 3*9 = 27
[6] = 6/2 = 3
27*3 = 81

The right answer is 27 .... The only way to obtain this value is to consider:
[9]x[6] = [81] = [3*m] => m = 27
By the way the question asks to give a value to [9]x[6] ...

What is the original source of this question? And please post all the answer choices--thanks!