X & Y & Z.....PT 2

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Source: — Data Sufficiency |

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Re: X & Y & Z.....PT 2

by drgmatIL » Mon Aug 18, 2008 3:14 am
smclean23 wrote:If x, y, and z are positive numbers, is x > y > z ?

(1) xz > yz
(2) yx > yz


Answer is E.
1. can be written like this X>Y but does Y>z? insufficient
2. can be written like this X>Z but does Y>Z and Y<X ? insufficient
1+2 = X>Y and X>Z but does Y>Z? insufficient

hope it helps

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by siddhans » Thu Oct 27, 2011 1:40 am
Is this correct way to solve ?

1) xz - yz > 0

z(x-y) > 0

z> 0 or x > y

No info about z in relation with x and y ---> Insufficient

2) y(x-z)>0

y > 0 or x > z

No info about y in terms of x and x ---> Insufficient

1 + 2 combined,

z > 0 and x > y OR z<0 and x<y

OR

y>0 and x>z OR y< 0 and x < z


Insufficient


Hence E