Problem Solving

Hi guys,

I have a quick question that I am unsure about in terms of how variables are presented in questions:

Example:
If ab ≠ 0, does a = b?

(1) xa = xb
(2) x = x2


here does "ab" indicate "a" times "b" (3 x 4 so ab would be 12) or a 2 digit number "ab" (15 where a is 1 and b is 5).


I have seen "ab" in a few different questions where it represents each scenario. Or is it only a 2 digit number when they state - ab is a positive two digit integer? Can I assume it mean a times b unless it says otherwise?

Thanks.

Ah, great question.

Unless the question says "a and b are digits" or somehow calls them out as individual digits and not full numbers, then ab is the product of a times b.

Another thing to keep in mind - that "If ____ ≠ 0" in Data Sufficiency is almost always a disclaimer to mean that none of the numbers in that product equals 0. So get used to seeing that kind of language in there.

So, yes, unless you're told otherwise "ab" means a times b. (and hint on this one - they told you that neither a nor b is equal to 0 in that question stem...but they didn't say anything about x).

Thank you for the clarification. Very helpful!