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Source: — Data Sufficiency |
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by mals24 » Sun Aug 10, 2008 11:44 am
st 1 says 2x-2y=1

2(x-y)=1
x-y=1/2

x could either be 0 and y = -1/2
or x could also be 1 and y = 1/2

hence st1 INSUFF

st 2 x/y>1
either x&y both are negative or both are positive INSUFF

Combining (1) & (2)
from st 1 let x=1/2+y............equ 1
substitute it in st 2: (1/2+y)/y>1
1/2y + 1 > 1
Subtract 1 from both sides
1/2y>0
hence y>0 i.e. y is positive
substituting it in equ1
x=(1+2y)/2 which is >0
Hence x is also positive

Answer is C
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by rhymes_with_luck » Sun Aug 10, 2008 1:03 pm
another approach

x/y>1

hence x/y -1 >0

or (x-y)/y >0

from 1 we know x-y>0

hence y>0 ....follows x>0 from 1

hence C
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by jimmytwoshoes » Mon Aug 11, 2008 7:48 am
Combining both equations:

1. x-y =1/2
2. x>y

Couldn't both the following be true:

x=3/4, y=1/4

x=1/4, y=-3/4

Shouldn't the answer be E?

Thanks!
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by jimmytwoshoes » Mon Aug 11, 2008 7:49 am
Sorry, duh..... I figured it out.
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by dhanda.arun » Mon Aug 11, 2008 6:45 pm
IMO the answer is E.
Because
from 1:- x-y = 1/2
from 2: x>y

x = 1 , y = 1/2
and
x = 1/4 y= -1/4
both satisfy these equations.
So the sign of x and y cant be determined.
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by mals24 » Wed Aug 13, 2008 6:20 am
x and y both cannot have different signs because x/y>1 according to st 2
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by kiran.raze » Thu Aug 14, 2008 7:34 pm
Hey guys,

I feel the answer should be E , just tryin to think aloud here.

x-y=1/2
x>y

either of them are insufficient as already agreed. Now combining both we have

X Y X>Y
1 1/2 True
-1/2 -1 True

so then shouldnt the answer be 'E'

thanks,
Kiran
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