Is x-y > x+y - DS question

[Guest]

[url=http://www.postimage.org/image.php?v=Pq1JyA_i][img]http://www.postimage.org/Pq1JyA_i.jpg[/img][/url]
Please help me with the solution.

Thanks!

[RonPurewal]

ok, i've had a really good day, so i'll be a perfect gentleman and type this question out.

DO NOT POST IMAGE FILES UNLESS YOU NEED IMAGE FILES.

this means never for verbal problems (which are always words, words, and more words), and for quant problems only if there are diagrams and/or formulas involving awkward things like roots or fractions.

this is particularly bad form, because this problem can easily be typed in 15 seconds.

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here's the problem:

if x - y > 10, is x - y > x + y ?

(1) x = 8

(2) y = -20

[RonPurewal]

if x - y > 10, is x - y > x + y ?

(1) x = 8

(2) y = -20

note that you can subtract x from both sides of the inequality, and add y to both sides, giving "is 0 > 2y?"
then divide by 2: "is 0 > y?"

so, the question is asking
"is y negative?"

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don't forget that x - y > 10!

statement (1)
if x = 8, then 8 - y > 10.
subtract 8 to give -y > 2, or, y < -2
so y is negative
sufficient

statement (2)
y is negative
sufficient

ans = d

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notice that this problem is a "C TRAP" - a problem on which both statements together are obviously sufficient (because the two statements together give numbers for ALL the variables in the problem).
on such problems, if you have to guess, you can make a safe bet that (c) is NOT the right answer (and, incidentally, neither is (e), because both statements together are, after all, sufficient).