power and inequality

[ska7945]

If x and y are positive, is x^3 > y?
(1) sqrt x > y
(2) x > y



oa C

[BILL]

If x and y are positive, is x^3 > y?
(1) sqrt x > y
(2) x > y

Are you sure this is posted correctly and/or the OA is correct?

Individually, both are insuff b/c there are some scenarios where x<1 where X or sqrtx can be greater than y but x^3 can be less than y. (try Y=.5 and then use X=.7 and X=100 to see what I mean)

In evaluting C, lets use X=.5 and Y=.3

sqrt x= ~.7 so it satisfies 1 and 2 b/c .7 and .5 are greater than .3 However, if we take x^3, we get .5x.5x.5 = .125<Y. If we plug in X=100, X^3 is clearly greater than Y. So E, insuff.

Would love to know if anyone disagrees/if I'm misreading...thanks

[sudhir3127]

If x and y are positive, is x^3 > y?
(1) sqrt x > y
(2) x > y



oa C

even i think its E. can u please share the source of the question!!

[parallel_chase]

Statement I

sqrtx = 1/2
y=1/4
sqrt x > y
x^3=1/8
x^3<y
No.

sqrtx = 2
x=4
y=5
x^3=64
y=5
x^3>y
Yes.

Insufficient.

Statment II
x>y
x=4
y=3
x^3=64
x^3>y
Yes.

x=1/2
y=1/4
x^3=1/8
x^3<y
No.
Insufficient.


Combining I & II

sqrt x > y
x > y

x=4
y=1
sqrtx =2

x^3>y
Yes.

x=1/4
sqrtx=1/2
y=1/8

1/4>1/8
1/2>1/8

1/8=1/8
x^3=y
No.

Insufficient.

Hence E.

The OA is wrong unless the question is posted incorrectly.

Whats the source.

[ska7945]

sorry i was also confused with q's.
i thought it was E, too.
neway, i downloaded this question from web.
it is in zip file and called gmat.
thats all i know.
sorry