Hi, I found this problem in GMAT Club test 10:
If X and Y are prime integers, what is |X - Y|?
1) X + Y is a prime integer.
2) X and Y are less than 5.
My answer was B, 2 is sufficient. However, official answer is C. The explanation is that X and Y could be the same integer. This is probably a very basic question to ask, but I though that if you assigned two different variables, they would stand for two different value. E.g. If X =2, then Y cannot also equal 2.
Could someone clarify for me whether two different variables in a GMAT problem can, indeed, have the exact same value? E.g. X=Y. What is the standard convention in mathematics?