wxy

This topic has expert replies
User avatar
Master | Next Rank: 500 Posts
Posts: 232
Joined: Fri Jun 18, 2010 7:09 am
Thanked: 1 times
Followed by:2 members

wxy

by ruplun » Thu May 26, 2011 6:37 am
Is wxy equal to -1?

(1) w,x and y are all negative
(2) w+x+y = -3
Source: — Data Sufficiency |

User avatar
Master | Next Rank: 500 Posts
Posts: 324
Joined: Mon Jul 05, 2010 6:44 am
Location: London
Thanked: 70 times
Followed by:3 members

by kmittal82 » Thu May 26, 2011 6:51 am
(1)
wxy could be any 3 negative numbers, not sufficient

(2)
4 + 5 + (-12) = -3 (in which case wxy is not equal to -1)
-1 + (-1) + (-1) = -3 (in which case wxy is equal to -1)

So, not sufficient

(1) + (2)

-0.5 + (-1) + (-1.5) = -3 (wxy is not -1)
-1 -1 -1 = -3 (wxy is -1)

Hence, even combined its not sufficient

Hence (E)

OA?

User avatar
Master | Next Rank: 500 Posts
Posts: 150
Joined: Tue Aug 18, 2009 7:36 am
Location: gurgaon
Thanked: 8 times
Followed by:2 members

by itsmebharat » Thu May 26, 2011 6:56 am
the answer should be E

To prove wxy = -1

(1) w=x=y= negative , it could be anything -4,-2,-5
1 alone not sufficient

(2) w+x+y= -3

5+4-12=-3 12+3-12
2 alone not sufficient

both together,
xyz are negative and sum should be -3
-1 -1 -1 = -3

-0.5 -2 -0.5 = -3
Also, not Sufficient.
Last edited by itsmebharat on Thu May 26, 2011 6:59 am, edited 1 time in total.
I am not an Expert, please feel free to suggest if there is an error.

User avatar
Master | Next Rank: 500 Posts
Posts: 324
Joined: Mon Jul 05, 2010 6:44 am
Location: London
Thanked: 70 times
Followed by:3 members

by kmittal82 » Thu May 26, 2011 6:59 am
itsmebharat wrote: both together,
xyz are negative and sum should be -3
-1-1-1 = -3
Sufficient
But can we assume w,x and y are whole numbers? The question doesn't state that, so it should be legal to use decimal values for those numbers too, in which case the product would not be -1 (as shown in my posting)

User avatar
Master | Next Rank: 500 Posts
Posts: 150
Joined: Tue Aug 18, 2009 7:36 am
Location: gurgaon
Thanked: 8 times
Followed by:2 members

by itsmebharat » Thu May 26, 2011 7:01 am
I agree, while assuming I made that mistake, thanks for correction. I edited my post.
I am not an Expert, please feel free to suggest if there is an error.