The answer has been stated, it can be either because it's poorly stated. Here's one of the better explanations I've read, copy/paste.

A similar debate popped up not that long ago and had people arguing non-stop. Check the reference at the bottom. The real answer is that the equation itself is ambiguous and should have been written better. This equation should have been written as...

( 6 / 2 ) * ( 1 + 2 ) =

or

6 / [ 2 ( 1 + 2 ) ] =

Using the standardized order of operations...
6 / 2 ( 1 + 2 )
6 / 2 ( 3 ) or 6 / 2 * 3
Answer = 9

Using parenthetical implications via multiplication by juxtaposition and the distributive property...
6 / 2 ( 1 + 2 )
6 / [ ( 2 * 1 ) + ( 2 * 2 ) ]
6 / 6
Answer = 1

Both of you are correct. Considering the ambiguity and poor nomenclature of the equation, you should ask whomever posed the problem to define his/her notation preferences. No self-respecting mathematician would write the equation in this manner.

Anytime you see ab/cd you will see this disagreement.

[link to answers.yahoo.com]