DS-Plz. help

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DS-Plz. help

by gmat009 » Tue Oct 07, 2008 12:39 pm
Is xy > (x^2)(y^2)
(1) 14(x^2) = 3
(2) y^2 = 1

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

OA is E , IMO C.

Can someone plz. explain

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Re: DS-Plz. help

by gmat2010 » Tue Oct 07, 2008 1:02 pm
gmat009 wrote:Is xy > (x^2)(y^2)
(1) 14(x^2) = 3
(2) y^2 = 1

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

OA is E , IMO C.

Can someone plz. explain
It's E because y can be either 1 or -1 from statement B. In that case, the answer will give you conflicting results.

It's a trick question, i first thought it was C as well...

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by raju232007 » Fri Oct 10, 2008 8:12 am
statement 1

14*x^2=3
x=sqrt(3/14),-sqrt(3/14)
This statement doesn't tell anything about the value of y
Insufficient

statement 2

y^2=1
y=1,-1

This statement doesn't tell anything about the value of x
Insufficient

Combining both the statements we have

4 cases should be considered
1.when both are positive
2.when both are negative
3.when x is positive and y is negative
4.when x is negative and y is positive


case 1
sqrt(3/14)*1>3/14*1....yes
(P.s the square root of a proper fraction results in a number greater than the fraction itself)

case 3
sqrt(3/14)*-1>-3/14.....The ans is no

Hence the ans should be E