Question from "How To Pass The GMAT"

[shanice]

Hi all,

The question below was supposed to be easy but unfortunately according to the answer , I got it wrong. I was really shocked. Can you guys help?

If x + 3y = 2x - y, then x - 2y is:

(A) 0
(B) 1
(C) 1/2
(D) 2/3
(E) Cannot be determined

Answer is A.

[Mike@Magoosh]

Hi, there. I'm happy to help with this.

If x + 3y = 2x - y, then x - 2y is:

Start with the original equation ...
(1) x + 3y = 2x - y
Subtract x from both sides ...
(2) 3y = x - y
Subtract 3y from both sides ...
(3) 0 = x - 4y

This expression does not allow us to determine the value of x - 2y, so the correct answer would be E.

I point out --- if the prompt equation had been...
x + 3y = 2x + y
...then the correct answer would be A.

What is the source? Perhaps they made a +/- sign when they printed the question. Or, it is possible that you transposed a +/- when you copied the problem from its source? Either way, you need the + sign instead of the - sign to get the answer that they claim is correct.

Does all this make sense? Let me know if you have any further questions.

Mike

[shanice]

Hi Mike,

That was the original question. I don't know what went wrong.

But I'm happy to know that my answer was right because I got E too.You've cleared my doubts.

Thank you so much, Mike.

[GmatKiss]

Easy A