if x, y, and z are integers

Hi,

please type out the questions rather than adding them as an attachment - it saves the people replying the work of typing them out, since you really need to look at the question to discuss it.

If x, y and z are integers, is x + y + 2z even?

Step 1 of the Kaplan Method for DS: Analyze the Stem

We see "is", we think "yes/no question: a definite yes is sufficient, as is a definite no; a "maybe" or "sometimes" is insufficient".

Since x, y and z are integers, 2z is always going to be even. So, we can simplify the question to:

Is x + y even?

Step 2 of the Kaplan Method for DS: Evaluate the Statements

(1) x + z is even.

No info about y, insufficient.

(2) y + z is even.

No info about x, insufficient.

Together:

We can write each statement as an equation:

x + z = even
y + z = even

and then add them together:

x + z + y + z = even + even

simplifying both sides:

x + y + 2z = even

Hey! That's exactly what the question is asking - so that's a definite "yes", sufficient. Choose (C).

Oh, and hey - please post in the right forum (this is a data sufficiency question, not problem solving!).

Stuart Kovinsky wrote:Oh, and hey - please post in the right forum (this is a data sufficiency question, not problem solving!).

Hi Stuart:

Yes 1, I should have typed the question, in fact, I did it on the first one I poested today, but, my exam is tomorrow so I need to save time as much as possible, so, it was easier, faster to attach it as image .. I know the easiest way is not always the right one ...

Yes 2, I posted it in the wrong forum, but again, I'm soooo hurried on this, that I didn't notice it ... Am I excused?

and thanks for your quick answer, actually, now that I see it, it was easy, but I didn't see it on the CAT ... so, not confident for tomorrow, even if I dont want a 800 !! ...

Thanks again Stuart for helping people u don't even know !
Silvia