BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

help

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 512
Joined: Mon Jun 18, 2012 11:31 pm
Thanked: 42 times
Followed by:20 members

help

by sana.noor » Mon May 13, 2013 3:48 am
Which of the following CANNOT be a value of x when
y = x/(x-1) ?
(A) -2
(B) -1
(C) 0
(D) 1/3
(E) 1

OA is E
Work hard in Silence, Let Success make the noise.

If you found my Post really helpful, then don't forget to click the Thank/follow me button. :)
Top
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 149
Joined: Wed May 01, 2013 10:37 pm
Thanked: 54 times
Followed by:9 members

by Atekihcan » Mon May 13, 2013 5:16 am
As the denominator of the expression on the right-hand contains (x - 1), x cannot be equal to 1 as that will make y = 1/0 which is indeterminate.

Answer : E
Top
User avatar
MBA Admissions Consultant
Posts: 2279
Joined: Fri Nov 11, 2011 7:51 am
Location: New York
Thanked: 660 times
Followed by:266 members
GMAT Score:770

by Jim@StratusPrep » Mon May 13, 2013 8:44 am
The denominator can never equal zero!
GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review

Image
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Mon May 13, 2013 9:33 am
"Fun" follow-up question:

Which of the following CANNOT be a value of y when y = x/(x-1) ?
(identify all correct answers)
(A) -2
(B) -1
(C) 0
(D) 1/3
(E) 1
(F) -1

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 149
Joined: Wed May 01, 2013 10:37 pm
Thanked: 54 times
Followed by:9 members

by Atekihcan » Mon May 13, 2013 10:07 am
Brent@GMATPrepNow wrote:Which of the following CANNOT be a value of y when y = x/(x-1) ?
x > (x - 1)

Now, if (x - 1) > 0, i.e. x > 1 ---> x/(x - 1) > 1
And, if (x - 1) < 0, i.e. x < 1 ---> x/(x - 1) < 1

So, x/(x - 1) can never be equal to 1.

Answer : E
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Mon May 13, 2013 10:12 am
Atekihcan wrote:
Brent@GMATPrepNow wrote:Which of the following CANNOT be a value of y when y = x/(x-1) ?
x > (x - 1)

Now, if (x - 1) > 0, i.e. x > 1 ---> x/(x - 1) > 1
And, if (x - 1) < 0, i.e. x < 1 ---> x/(x - 1) < 1

So, x/(x - 1) can never be equal to 1.

Answer : E
Good stuff.
Another approach is to recognize that, in order for x/(x-1) to equal one, the numerator must equal the denominator. Since it's impossible for x to equal x-1, the expression can never equal 1.

Aside: I added the bit about identifying all correct answers to see if anyone would bite and select F as well.

Cheers,
Brent
Last edited by Brent@GMATPrepNow on Mon May 13, 2013 10:54 am, edited 2 times in total.
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 149
Joined: Wed May 01, 2013 10:37 pm
Thanked: 54 times
Followed by:9 members

by Atekihcan » Mon May 13, 2013 10:52 am
Brent@GMATPrepNow wrote:Another approach is to recognize that, in order for x/(x-1) to equal zero...
You meant to say 'one', I guess.
Brent@GMATPrepNow wrote:Aside: I added the bit about identifying all correct answers to see if anyone would bite and select F as well.
B and F are same answer choice.
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Mon May 13, 2013 10:57 am
Atekihcan wrote:
Brent@GMATPrepNow wrote:Another approach is to recognize that, in order for x/(x-1) to equal zero...
You meant to say 'one', I guess.

Good catch. I edited it accordingly
Brent@GMATPrepNow wrote:Aside: I added the bit about identifying all correct answers to see if anyone would bite and select F as well.
B and F are same answer choice.
Another nice catch!
I guess I should have another cup of coffee :-)

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Post new topic Post Reply
• Page 1 of 1