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Junior | Next Rank: 30 Posts
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GMAT Prep

by TGE » Sat May 16, 2009 9:45 pm
Hello all,

Need help with understanding how to solve the following question efficiently:

Is xy > 0?

(1) x - y > -2
(2) x - 2y < -6

OA: C

Many thanks.[/spoiler]
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by cramya » Sat May 16, 2009 10:07 pm
I am assuming u probably got to determining that the 2 statements individually are not SUFF

1) x - y > -2
(2) x - 2y < -6 => - 6 > x- 2y

TOGETHER:

We can add inequalities facing same direction

x-y>-2
-6>x-2y

x-y + -6 > -2 + x - 2y

We get y>4

Lets say we keep y=4 and we know x - y>-2 i.e x > -2+y
x > -2+4
x>2

We can see that x and y are positive so xy>0

SUFF

C
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Junior | Next Rank: 30 Posts
Posts: 13
Joined: Sat May 16, 2009 9:14 pm
Location: New York

by TGE » Sun May 17, 2009 6:13 am
Makes sense. I was able to eliminate A,B and D, but was struggling between C and E. The part I was missing was lining up and adding the two inequalities.

Thanks for the help, Cramya.
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