Is the value of expression k – m + 1 greater than the expression k+ m – 1.

(1) k is greater than zero.

(2) m is less than zero.

So my train of thoughts were to simply this:

Is k - m + 1 > k + m - 1 ?

or

1 - m > m - 1

2 > 2m

Is m < 1 ?

Now the question is easier to answer.

Statement 1)

If k > 0, well it shouldn't matter what k is, so I thought this was okay, so I thought statement 1 is true.

Statement 2)

Clearly if m < 0, then m < 1. So statement 2) is true.

So I put down D as answer.

But for some reason, the answer choice is only statement 2) is true.

What's the explanation for that? Since in statement 1, it should not really matter a jot what k is?

Thanks as always for your help.

Best wishes.

Since as you said, IT does not matter. A and D can be elminated as wrong answer choices.

Kudos Please... If my post helped.
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Kudos Please... If my post helped.

Thanks To The Almighty - My GMAT Debrief
My Own CR Question 1|My Own CR Question 2|My Own DS Question 1|My Own DS Question 2|
My Own PS Question 1

Dear elegan,

Everyone else on the page said that you were wrong, but it's not clear to me that anyone explained in clearly enough so that you now fully understand the deeper issue at play here.

I'll begin by saying, here are a couple blogs you may find informative about DS in general.
http://magoosh.com/gmat/2012/introducti ... fficiency/
http://magoosh.com/gmat/2012/gmat-data- ... trategies/

You made a very classic DS mistake ---- confusing the "truth value question" with the "sufficiency question."

The prompt in this question is: "Is the value of expression k – m + 1 greater than the expression k+ m – 1?" That's a 'truth value question", about whether a mathematical statement is true or false. Technically speaking, we are not answering this question at all. Technically, our job on DS is to answer the "sufficiency question" --- viz., given this new piece of information, the DS Statement, would this piece of information allow me to determine a definitive answer to the prompt question?

When you look at a DS statement, your job is not to answer any of these questions
"is this true?"
"could this be true?"
"would it be OK if this were true?"
"is this consistent with the prompt?"
Rather, your job is very focused and specific: your job is to answer the single question
"Is this statement sufficient?"
i.e.
"If I were given this statement as a true piece of information, over and above whatever true pieces of info I have from the prompt, does this allow me to determine a definitive answer to the prompt question?"
All of math depends on precision. In DS, part of success is making sure that you are always answering the sufficiency question, and never any other question, when you evaluate these statements.

If you are considering a different question than the one you are supposed to consider, you will tend to get DS questions incorrect. For example, in this case, recognizing the value of K doesn't matter would lead to a resounding "yes!" if we were working with something like the question "could this be true?", but if we are working very strictly with the sufficiency question, irrelevance generally does not help us at all in determining anything definitively. If we focus precisely on the sufficiency question, we must arrive at a "no" answer here ---- statement #1 is not sufficient.

Does all this make sense?

Mike
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Mike McGarry
Magoosh Test Prep