Data Sufficiency

Is it C ?

Stmt I

2x-2y = 1

x-y=1/2

x=1 y=1/2
x=-1/2 y = -1

INSUFF

Stmt II
x/y>1

Both x and y are positive or both are negative

Combining I and II

x and y are both positive

C)

can u guys help me out here...

what if X = - 0.1 and Y = -0.6

X is Still Greater than Y; and X - Y is still 0.5(1/2)

Now, both are not positive..

Should the answer not be E?

Not sure what exactly I am missing here..

Not sure what exactly I am missing here

x/y > 1 is the one missing

Got ya

Thanks!

Ok here is an issue I have with this problem

statement II says that x/y > 1

can we also write this statement as x>y?

because if we convert this statement to x>y, the solution changes from C to E.

Here how it goes..

x = - 3.5
y = -4

x>y or -3.5>-4 (statement holds true)

2x - 2y = 1
or
-7 +8 = 1
1=1

we could also have:

x = 4 and y = 3.5 when both x and y are positive
x>y ------YES

2(4) - 2(3.5) = 1
8-7 = 1
1=1

Hence, E

For C to hold true we basically are forbidden to cross multiply the equation x/y > 1. Instead we are solving this equation as x/y - 1 > 0

statement II says that x/y > 1

can we also write this statement as x>y?

I dont think so since we dont know the sign of y

If y was positive then yes x>y but if y was negative then x<y

one more thing...
we have x=y+1/2 from 1 stmt.
put it in 2nd stmt
(y+1/2)/y > 1
1+(1/2y) > 1 or 1/2y > 0
which is only possible if y>0
and if y>0, x is also greater than 0 from 2.

Hope it helps.

jimmiejaz wrote:one more thing...
we have x=y+1/2 from 1 stmt.
put it in 2nd stmt
(y+1/2)/y > 1
1+(1/2y) > 1 or 1/2y > 0
which is only possible if y>0
and if y>0, x is also greater than 0 from 2.

Hope it helps.

this is great!

The answer has to be E

(1) x=0.5 y=0 or x=1 y=0.5

(2) simply says that x>y not Sufficient

(1) and (2) both not enough because in (1) for both options x>y

moneyman wrote:The answer has to be E

(1) x=0.5 y=0 or x=1 y=0.5

(2) simply says that x>y not Sufficient

(1) and (2) both not enough because in (1) for both options x>y

Hey moneyman,

We can't say x/y > 1 as x>y since we dont know that y is positive.
If y is negative, the eqn becomes x<y.
hope it helps.
So, the ans is C