Last visit was: 19 Jul 2025, 16:56 It is currently 19 Jul 2025, 16:56
Close
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
Your Progress

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
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
oloman
Joined: 19 Jun 2010
Last visit: 25 Jun 2016
Posts: 36
Own Kudos:
45
 [27]
Given Kudos: 17
Posts: 36
Kudos: 45
 [27]
2
Kudos
Add Kudos
25
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
VikashAlex
Joined: 22 Sep 2014
Last visit: 05 Jan 2016
Posts: 29
Own Kudos:
282
 [15]
Given Kudos: 12
Posts: 29
Kudos: 282
 [15]
11
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
User avatar
EMPOWERgmatRichC
User avatar
Major Poster
Joined: 19 Dec 2014
Last visit: 31 Dec 2023
Posts: 21,788
Own Kudos:
12,504
 [6]
Given Kudos: 450
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Posts: 21,788
Kudos: 12,504
 [6]
3
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
General Discussion
User avatar
oloman
Joined: 19 Jun 2010
Last visit: 25 Jun 2016
Posts: 36
Own Kudos:
45
 [2]
Given Kudos: 17
Posts: 36
Kudos: 45
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
thanks! makes sense,
So, can I just say that x^2 +1 >= 1 , so, 3/y>=1, then plug in answer choices and see which one wont satisfy?? The underlining lesson here is that x^2 can be 0 as well?
best

EMPOWERgmatRichC
Hi oloman,

To start, NOT every number that's squared is positive; squaring the number 0 will get you 0. Here though, since we're dealing with (X^2 + 1), that sum will always be AT LEAST 1. That piece of information is the 'key' to this question. Here's why:

We're given (X^+1)(Y) = 3

As (X^2+1) increases in value, Y will DECREASE in value.

So, when (X^2+1) = 1, we have...

(1)(Y) = 3 and Y = 3

But if X=1, then (X^2+1) = 2....

(2)(Y) = 3 and Y = 3/2

You'll find that no matter what value you plug in for X, Y can NEVER be greater than 3.

Final Answer:
GMAT assassins aren't born, they're made,
Rich
User avatar
EMPOWERgmatRichC
User avatar
Major Poster
Joined: 19 Dec 2014
Last visit: 31 Dec 2023
Posts: 21,788
Own Kudos:
Given Kudos: 450
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Posts: 21,788
Kudos: 12,504
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi oloman,

Yes, based on the concepts involved, your approach would absolutely work.

GMAT assassins aren't born, they're made,
Rich
User avatar
ENGRTOMBA2018
Joined: 20 Mar 2014
Last visit: 01 Dec 2021
Posts: 2,328
Own Kudos:
Given Kudos: 816
Concentration: Finance, Strategy
GMAT 1: 750 Q49 V44
GPA: 3.7
WE:Engineering (Aerospace and Defense)
Products:
GMAT 1: 750 Q49 V44
Posts: 2,328
Kudos: 3,791
Kudos
Add Kudos
Bookmarks
Bookmark this Post
VikashAlex

Its simple
equation is (x^2 +1)y = 3 ===> x^2 = (3/y) - 1 . As , in LHS, it is x^2 the value has to be positive or zero in RHS.
Hence, (3/y) - 1>= 0 ===> y =< 3. Now only option E has greater value of 'y' than 3.
Thus, correct ans is E

+1 kudos if it helped you

A bit of correction in your solution. The text in red above is not the complete range. The complete range of values of y from 3/y-1 \(\geq\) 0 will be 0 \(\leq\) y \(\leq\) 3
User avatar
VikashAlex
Joined: 22 Sep 2014
Last visit: 05 Jan 2016
Posts: 29
Own Kudos:
Given Kudos: 12
Posts: 29
Kudos: 282
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Engr2012
VikashAlex

Its simple
equation is (x^2 +1)y = 3 ===> x^2 = (3/y) - 1 . As , in LHS, it is x^2 the value has to be positive or zero in RHS.
Hence, (3/y) - 1>= 0 ===> y =< 3. Now only option E has greater value of 'y' than 3.
Thus, correct ans is E

+1 kudos if it helped you

A bit of correction in your solution. The text in red above is not the complete range. The complete range of values of y from 3/y-1 \(\geq\) 0 will be 0 \(\leq\) y \(\leq\) 3

Hi,
Yes, its true the y range will be 0 ≤ y ≤ 3. Missed it 0 part. But in any case the option E does not fall in between this reason.
Thank you for pointing out. This is the silly thing that I miss during DS ques.
User avatar
nikhiljd
Joined: 01 Apr 2014
Last visit: 19 Aug 2017
Posts: 36
Own Kudos:
Given Kudos: 93
Schools: ISB '17
GMAT 1: 530 Q35 V28
GPA: 2.5
Products:
Schools: ISB '17
GMAT 1: 530 Q35 V28
Posts: 36
Kudos: 20
Kudos
Add Kudos
Bookmarks
Bookmark this Post
y=3/(x^2+1) => y<=3
for all answer choices y<=3 except E
ans E
User avatar
arvind910619
Joined: 20 Dec 2015
Last visit: 18 Oct 2024
Posts: 850
Own Kudos:
Given Kudos: 755
Status:Learning
Location: India
Concentration: Operations, Marketing
GMAT 1: 670 Q48 V36
GRE 1: Q157 V157
GPA: 3.4
WE:Engineering (Manufacturing)
Products:
GMAT 1: 670 Q48 V36
GRE 1: Q157 V157
Posts: 850
Kudos: 601
Kudos
Add Kudos
Bookmarks
Bookmark this Post
IMO E
3\(x^2+1)=Y
From the above equation we can infer that the value of y <=3
We have X^2 in denominator which is always positive.
User avatar
KarishmaB
Joined: 16 Oct 2010
Last visit: 19 Jul 2025
Posts: 16,115
Own Kudos:
74,407
 [4]
Given Kudos: 475
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,115
Kudos: 74,407
 [4]
3
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
oloman
If (x^2 + 1)y=3, which of the following is not a possible value for y?

A. 3/2
B. 2
C. 8/3
D. 3
E. 7/2

This is from a Kaplan CAT test.

Kaplan states that "The variable x is being squared, and we know that whenever any value is squared, the result is always a positive number"
So when I do the match with a, b and c I understand how those can be values for y given that x^2 = a positive number.
For D however, you will get x^2=0, now here is where I have my question. According to the web, zero is neither positive nor negative, according to kaplan's explanation, any squared number must be a positive number, then how can x^2=0 be correct in saying that x^2= a positive number if 0 is nor positive nor negative.
For e, I understand that x^2 = (a negative number) hence this cannot be a value so this is not a possible value of y.


I understand why e is correct, but I do not understand why D is technically wrong!, can someone please help?
best
Oloman

The only constraint of \((x^2 + 1)*y=3\) is that \(x^2\) cannot be negative.

So, \(x^2 = 3/y - 1\)
\(3/y - 1\) cannot be negative.
Plug in the values to see which one gives a negative value.

\(3/y - 1\)

Only option (E) gives you a negative value.
User avatar
JeffTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 04 Mar 2011
Last visit: 05 Jan 2024
Posts: 2,996
Own Kudos:
Given Kudos: 1,646
Status:Head GMAT Instructor
Affiliations: Target Test Prep
Expert
Expert reply
Posts: 2,996
Kudos: 7,952
Kudos
Add Kudos
Bookmarks
Bookmark this Post
oloman
If (x^2 + 1)y=3, which of the following is not a possible value for y?

A. 3/2
B. 2
C. 8/3
D. 3
E. 7/2

We are given that (x^2 + 1)y = 3.

Since x^2 is always nonnegative, we see that x^2 + 1 must always be greater than or equal to 1. Thus, in order for the product of a number greater than or equal to 1 and y to be 3, y has to be less than or equal to 3. Thus, y cannot equal 7/2.

Answer: E
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 37,451
Own Kudos:
Posts: 37,451
Kudos: 1,013
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderators:
Math Expert
102627 posts
PS Forum Moderator
698 posts