gmat prep DS

[basili.alukos]

Hi All,

Does anyone know how to solve this question?

Does
x - y = 200?
(1) X=10^2
(2)x = 100 and y = -100

I thought the answer was d, cause if you substitute 100 (from stmt 1) into the equation, you can solve for Y.

the answer is just B but I don't get it.

Thanks,

[rp.tina]

x-y=200 is not a given. They are asking us to find out whether that is true. So, we cannot substitute the value of X in order to find Y.

Hope this helps.

[RonPurewal]

x-y=200 is not a given. They are asking us to find out whether that is true. So, we cannot substitute the value of X in order to find Y.

Hope this helps.

this is an accurate summary; thanks.

to the original poster, you would be well advised to go back to the very basics of data sufficiency, and make sure you understand what is actually going on in a data sufficiency problem before you make further attempts at solving such problems.
right now you are confusing the question with the statements -- an absolutely fundamental error that will pretty much prevent you from solving any problem correctly.
try going to the beginning of the data sufficiency chapter in OG (i think it's chapter 6) and re-reading the information about how data sufficiency problems work.