A good ds@

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A good ds@

by m51v50 » Sun May 25, 2008 4:08 am
If –2x > 3y, is x negative?
(1)y > 0
(2) 2x + 5y – 20 = 0
Have 790 or die

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by ksh » Sun May 25, 2008 9:01 am
From the stimuli, -2x>3y gives x/y>-3/2

stem 1. y>0, if y is greater than 0, for x/y>-1.5 x may be +ve or -ve. NS
stem 2. 2x+5y-20=0
5y=20-2x
y=2/5*(10-x)
=0.4(10-x), x may have any value. NS

1+2, for y>0, x may be +ve or -Ve. hence NS

Is the ans E?

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by aatech » Sun May 25, 2008 6:26 pm
I will go with D

Stmt 1 - y is +ve means 3y is +ve.. so, if -2x>3y that means x is -ve... SUFF

Stmt 2 - 2x+5y = 20..... (1)

q we have -2x>3y => 2x+3y < 0 .... (2)

Eq 1 can be written as 2x+3y+2y = 20.. from eq 2 we know 2x+3y is -ve. So, to satisfy eq 1 2y must be greater than 20. means y is +ve.. then same explanation as stmt 1... SUFF

OA??

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by akshatsingh » Mon May 26, 2008 9:40 pm
I too think its D.

whats the OA ?
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by kausis » Tue May 27, 2008 4:54 am
The answer should be D.

-2x > 3y ----------------- (1)
=> 2x <3y> x <3> -2x = 5y – 20
Substituting in eq(1),
5y – 20 > 3y
2y > 20
y > 10
So from eqn (2), if y >10, then x must be negative.

Hence the answer is [D]

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The equation is simplified as

by shiraj » Fri May 30, 2008 1:09 am
The equation is simplified as
x < - ((3/2)y)

Now, we have -
Condition 1 -
gives y > 0, then x is always negative.

Condition 2 -
gives y > 10, than x is always negative.


Hence D