GMAT Question of the Day: Data Sufficiency

Basant
#1. August 23rd, 2008, at 9:39 PM.

i think its D..
considering that its x^2 and y^2 so any value of x or y we take either negative or positive, its square is going to be positive….
hence x^2=9y^2
hence x^2 will always be greater than y^2…

Vamsi Krishna Kanuri
#2. August 24th, 2008, at 9:36 AM.

D

shilpa
#3. August 24th, 2008, at 4:55 PM.

D

kapil
#4. August 24th, 2008, at 5:56 PM.

D

Laura
#5. August 24th, 2008, at 8:46 PM.

Aren’t the statements unnecessary?

If x = 3y, the question is asking if (3y)^2 > y^2. Negative/positive isn’t going to matter because it’s being squared, and 3/fraction squared is always going to be bigger than 1/same fraction squared. So - why are the two statements necessary at all?

Carolalo
#6. August 25th, 2008, at 6:03 AM.

I agree with Laura

AMIT kUMAR
#7. August 25th, 2008, at 9:22 AM.

None of the statements are necessary .it can be answered on its oqwn.

vikas sharia
#8. August 25th, 2008, at 12:14 PM.

Yes laura’s ans goes with the right approach.

Sandeep
#9. August 25th, 2008, at 12:43 PM.

B

Ankur
#11. August 26th, 2008, at 2:58 PM.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

Pooja
#12. August 28th, 2008, at 4:25 PM.

1) y+x>y-x
take y = 3, x=2
then 5>1
take y=2, x=3
again 5>-1
hence insufficient

2) x^2 = 9y^2
sufficient

Immanuel Ashok
#13. August 29th, 2008, at 9:36 AM.

B is the correct answer! i.e Statement 2 alone is sufficient to answer the question.

The question is - Is x^2 > y^2?

From statement (2) we find that x^2 > 9y^2. i.e X squared is greater than 9 times Y squared! Here, we are checking only for squared quantitites. Therefore it can be safely established that X squared is greater than Y squared.

In case of statement (1) the value of y cancels out y-y on moving y to any side. and we are left with 2x>0. This can only mean that x>0 and says nothing of y. Hence we are unable to answer the question is x^2>y^2 from this statement.

Alex
#14. September 12th, 2008, at 12:17 PM.

The answer is A.

x^2 > y^2 will ALWAYS hold true EXCEPT the case where x = y = 0. 1) y+x > y-x implies that x and y cannot be equal to zero both at the same time (0 > 0 -> FALSE), so it is sufficient to answer the question.

Chandan
#15. October 20th, 2008, at 10:03 PM.

Take GMAT team…. Please give the correct answer.