Mr_T wrote:It's from the Prep test:
Are x and y both positive?
1) 2x - 2y = 1
2) x / y > 1
It's probably easy, but I don't see how you can answer the question with these two equations.
Thanks,
mr T
Simple Approach
Statement 1: x-y=1/2
Either both are positive or both are negative... Not clear... Insufficient
Statement 2: X/Y>1
Either Both are positive or both are negative for this to be true... Not clear... Insufficent
Also, absolute value in numerator has to be > denominator. But that does not rule out the possibility of either being positive or negative...not Clear... Insufficient
In any case... |x|>|y| for this condition to be true
Jointly
For x/y>1, there are only two conditions
a. If both are positive; which satisfies equation 1
b. If both are negative, with |x|>|y|; which makes the equation 1 impossible to be true
e.g. if X=-7/2 and Y=-3.. Equation 1 will be -7/2+3=-1/2 and not 1/2 as the equation prescribes
So decisively, Both are positive... Hence C
Alternatively
if X-Y=1/2, there are only two possibilities
a. If both are positive. Then, Clearly X>Y... Satisfies equation 2
b. If both are negative. Then, |y|>|x|...and condition 2 is opposite of this (|x|>|y|)... Not possible...
So decisively, Both are positive... Hence C
