Question from GMAT Prep

[mpaudena]

I've got Windows Vista and it doesn't allow me to view the explanations to the CAT tests that I've taken. I have a question. Any help would be greatly appreciated:

For all positive intergers m #m# = 3m when m is odd and 1/2m when m is even. Which of the following is equivalent to #9# x #6#?

My answer was 81 and they said the answer was 27. Any one know why? Thanks in advance.

[Ian Stewart]

I've got Windows Vista and it doesn't allow me to view the explanations to the CAT tests that I've taken. I have a question. Any help would be greatly appreciated:

For all positive intergers m #m# = 3m when m is odd and 1/2m when m is even. Which of the following is equivalent to #9# x #6#?

My answer was 81 and they said the answer was 27. Any one know why? Thanks in advance.

The answer isn't 27; it's #27#, which is equal to 81. Notice that none of the answer choices are numbers - the function is applied in each answer choice. Easy trap to fall into!

[mpaudena]

Tricky. Thanks.

[Ian Stewart]

Definitely tricky. I'd add that GMATPrep doesn't have explanations no matter what operating system you're on, Vista or otherwise.