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Source: — Data Sufficiency |

by cramya » Mon Dec 01, 2008 10:16 pm
Can u please check if OA is [spoiler]B)[/spoiler] ?

I must be misisng something if not.... I will check again
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by vittalgmat » Tue Dec 02, 2008 12:13 am
I am getting B.. can u pls check the OA.
Here is my approach.

Cramya, Logitech. Pls let me know if I have messed up.


stmt 1:
x^2 / (xy -x) < 1
This can be simplified coz x and y != 0 (the min requirement)
so simplying
x/(y+1) < 1
= x < y+1

We are not sure whether x < y. since x < (y+1), x could be = y or >y

So insufficient.

Stmt2:
xy/(y^2 -y) < 1
again simplifying
x/(y-1) < 1
= x < y-1
x is less than y-1. Hence x is definitely less than y.
Sufficient.
B
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by cramya » Tue Dec 02, 2008 8:24 pm
Vittal, I think u r ok there!
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by gmataug08 » Tue Dec 02, 2008 9:14 pm
stmt 2 can be solved as x < y-1 , as both positive, that sure implies x is less that y

I am too going with B
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by Carloblacksun » Tue Dec 02, 2008 11:19 pm
I confirm that B is the answer for me too...same conclusion as you!
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by logitech » Tue Dec 02, 2008 11:40 pm
vittalgmat wrote:I am getting B.. can u pls check the OA.
Here is my approach.

Cramya, Logitech. Pls let me know if I have messed up.


stmt 1:
x^2 / (xy -x) < 1
This can be simplified coz x and y != 0 (the min requirement)
so simplying
x/(y+1) < 1
= x < y+1

We are not sure whether x < y. since x < (y+1), x could be = y or >y

So insufficient.

Stmt2:
xy/(y^2 -y) < 1
again simplifying
x/(y-1) < 1
= x < y-1
x is less than y-1. Hence x is definitely less than y.
Sufficient.
B
vittalgmat, your solution looks good. But I hope you know why the sign did not change when you got:

x/(y-1) < 1
= x < y-1

Because you know that Y-1 is a positive number right ? Otherwise you could have gotten into trouble!
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
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by vittalgmat » Wed Dec 03, 2008 12:27 am
Yep I did Logitech.. Thanks for pointing me out.
I was 90% sure .. now coz u pointed it out, I will remember this!!
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by bacali » Thu Dec 04, 2008 3:09 pm
sorry guys, the sets aren't very reliable. At least not the ones I have.
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by cramya » Thu Dec 04, 2008 4:05 pm
sorry guys, the sets aren't very reliable. At least not the ones I have.
I agree. Its good to get it clarified when in doubt.

Regards,
Cramya
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