OA: A Why is B insufficient : Quant Question Archive [LOCKED]
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 18 Jan 2017, 03:58

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

OA: A Why is B insufficient

Author Message
Intern
Joined: 04 Feb 2007
Posts: 29
Followers: 0

Kudos [?]: 0 [0], given: 0

OA: A Why is B insufficient [#permalink]

Show Tags

08 Feb 2007, 19:15
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

OA: A

Why is B insufficient?
Attachments

-.JPG [ 43.01 KiB | Viewed 532 times ]

Senior Manager
Joined: 04 Jan 2006
Posts: 279
Followers: 1

Kudos [?]: 37 [0], given: 0

Show Tags

08 Feb 2007, 19:52
Question: x, y >= 1, Is x = (integer value) * y?

...(1) 3y^2 - 7y = x
y(3y-2) = x
Because y is an integer >=1, (3y-2) will always be an integer. SUFF

...(2) x^2 - x = (integer value) * y; assuming integer value = k

x(x-1) = ky

x = [k/(x-1)] * y

Because [k/(x-1)] could be either integer or fraction number. INSUFF.

Manager
Joined: 10 Dec 2005
Posts: 112
Followers: 1

Kudos [?]: 4 [0], given: 0

Show Tags

08 Feb 2007, 22:08
joyce wrote:
OA: A

Why is B insufficient?

Is x = ky?

From condition 1 we know y(3y+7) = x ==> x = ky where 3y+7 = k, k will always be an interger as y is an integer hence we proved x =ky sufficient

From condition 2 we know (x^2 - x) = ky ==>ky = x(x-1) ==> x = (k/x-1) * y ==> here k/x-1 will not be an integer and hence not sufficient

_________________

"Live as if you were to die tomorrow. Learn as if you were to live forever." - Mahatma Gandhi

Re: Gmatprep - inequality   [#permalink] 08 Feb 2007, 22:08
Display posts from previous: Sort by