Data Sufficiency

how do we know about y ?

ifthyder wrote:how do we know about y ?

x>y>z ?

1) xz>yz, since x y and z are positive numbers we can simplify this
x>y. we dont know anything about z. Insufficient.

2) yx>yz, since x y and z are positive numbers we can simplify this
x>z, we dont know anything about y. Insufficient.

Combining 1 & 2

We still dont know about the relationship between z and y. Insufficient.

Thus, E is the answer.

I think it's E too, agree with Morgoth's explanation.

Subtract 1 from 2, you shall get

xz-yx>0

x(z-y)>0

therefore, either both x and z-y>0 or x and z-y <0
but we know X>0 ( x is given as positive) hence z-y>0, z>y.

Hence C

sumithshah:

I don't think you can subtract inequality equations.



Please share your thoughts.

EricLien9122 wrote:sumithshah:

I don't think you can subtract inequality equations.



Please share your thoughts.

You can subtract inequality equations. But there are some operations like multiplication, division and squaring that you can do only after considering the sign of the variables in question.

Cheers.

what is the OA

sumithshah wrote:Subtract 1 from 2, you shall get

xz-yx>0

x(z-y)>0

therefore, either both x and z-y>0 or x and z-y <0
but we know X>0 ( x is given as positive) hence z-y>0, z>y.

Hence C

I can subract the other way around, in which case I would get y>z.

I think it is E.