Last visit was: 24 Mar 2025, 12:48 It is currently 24 Mar 2025, 12:48
Home
GMAT
Messages
Tests
Schools
Reviews
Rewards
Chat
My Profile
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
505-555 Level|   Algebra|      
User avatar
pradeepss
User avatar
Joined: 19 Sep 2008
Last visit: 21 Dec 2014
Posts: 69
Own Kudos:
210
 [28]
Given Kudos: 257
Status:Please do not forget to give kudos if you like my post
Location: United States (CA)
Posts: 69
Kudos: 210
 [28]
If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x Updated on: 05 Jun 2019, 05:23
Originally posted by pradeepss on 09 Oct 2013, 20:05.
Last edited by Bunuel on 05 Jun 2019, 05:23, edited 3 times in total.
Renamed the topic and edited the question.
1
Kudos
Add Kudos
27
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

15% (low)

Question Stats:

75% (01:01) correct 25% (01:03) wrong based on 897 sessions

History

Date
Time
Result
Not Attempted Yet
If \(x = \frac{1}{2}\), is y equal to 1?


(1) \(y^2(x + 1/2) = 1\)

(2) \(y(2x - 1) = 2x - y\)

Show Spoiler
why is GMAT so biased on sqr(y) = 1. I mean, why sqroot(y) not equal to 1, instead it is + or - 1? for GMAT \sqrt{1} = 1
ShowHide Answer
Official Answer
B
Most Helpful Reply
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 24 Mar 2025
Posts: 20,384
Own Kudos:
25,431
 [8]
Given Kudos: 292
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 20,384
Kudos: 25,431
 [8]
If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x 11 Oct 2016, 16:56
6
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
pradeepss
If x = 1/2, is y equal to 1?

(1) y^2(x + 1/2) = 1
(2) y(2x - 1) = 2x - y

We are given that x = ½ and we must determine whether y = 1.

Statement One Alone:

y^2(x + ½) = 1

We can substitute ½ for x in the equation:

y^2(x + ½) = 1

y^2(1/2+ 1/2) = 1

y^2(1) = 1

y^2 = 1

y = 1 or y = -1

Statement one is not sufficient to answer the question. We can eliminate answer choices A and D.

Statement Two Alone:

y(2x – 1) = 2x – y

We can substitute ½ for x in the equation:

y(2x – 1) = 2x – y

y(2(1/2) – 1) = 2(1/2) – y

y(1- 1) = 1 – y

y(0) = 1 – y

0 = 1 – y

y = 1

Statement two alone is sufficient to answer the question.

Answer: B
General Discussion
User avatar
shameekv
User avatar
Joined: 29 Aug 2013
Last visit: 11 Aug 2020
Posts: 51
Own Kudos:
177
Given Kudos: 26
Location: United States
Concentration: Finance, International Business
GMAT 1: 590 Q41 V29
GMAT 2: 540 Q44 V20
GPA: 3.5
WE:Programming (Computer Software)
GMAT 2: 540 Q44 V20
Posts: 51
Kudos: 177
If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x 09 Oct 2013, 22:12
Kudos
Add Kudos
Bookmarks
Bookmark this Post
pradeepss
if X = 1/2, is Y equal to 1?

1. Y(X+1/2) = 1
2. Y(2X-1) = 2X - Y

Show Spoiler
why is GMAT so biased on sqr(y) = 1. I mean, why sqr(y) not equal to 1, instead it is + or - 1? for GMAT \sqrt{1} = 1

Hey Pradeep,

Are you sure of the OA. And is the 1st statement \(Y*(X+\frac{1}{2}) = 1\)??

Because if that is so then it is sufficient. We can substitute value of X = 1/2 in this and we certainly get Y = 1. I don't believe there is any trick here? Can someone kick in here?

And by the way about your query on \(\sqrt{Y^2}\) you can visit the following link where Bunuel has explained it very nicely.

https://gmatclub.com/forum/confusion-on-square-roots-127807.html

For this question my Answer would be D.

Consider Kudos if the post helps. :-D
User avatar
pradeepss
User avatar
Joined: 19 Sep 2008
Last visit: 21 Dec 2014
Posts: 69
Own Kudos:
210
Given Kudos: 257
Status:Please do not forget to give kudos if you like my post
Location: United States (CA)
Posts: 69
Kudos: 210
If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x 09 Oct 2013, 22:49
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Shameek,

You have the correct expression for 1.
I read in MGMAT guides as follow:
if square of Y = 1, then Y = + or - 1. GMAT approach is, if Y = 1 then square of Y = 1 and if Y = -1 the square if Y is still 1.

Hope that helps.
User avatar
shameekv
User avatar
Joined: 29 Aug 2013
Last visit: 11 Aug 2020
Posts: 51
Own Kudos:
177
Given Kudos: 26
Location: United States
Concentration: Finance, International Business
GMAT 1: 590 Q41 V29
GMAT 2: 540 Q44 V20
GPA: 3.5
WE:Programming (Computer Software)
GMAT 2: 540 Q44 V20
Posts: 51
Kudos: 177
If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x 10 Oct 2013, 00:44
Kudos
Add Kudos
Bookmarks
Bookmark this Post
pradeepss
Shameek,

You have the correct expression for 1.
I read in MGMAT guides as follow:
if square of Y = 1, then Y = + or - 1. GMAT approach is, if Y = 1 then square of Y = 1 and if Y = -1 the square if Y is still 1.

Hope that helps.

First of all I would like to know where does square of Y comes into picture in this question. If you open the 1st statement's expression you get

\(X*Y + (\frac{Y}{2}) = 1\)

which will be \(\frac{Y}{2} + \frac{Y}{2} = 1\)

i.e. Y = 1 - Hence Sufficient

For the second statement :-
Y*(2X-1) = 2X - Y

2XY - Y = 2X - Y

i.e. 2XY - 2X = 0

i.e. 2X(Y-1) = 0

either X = 0 or Y = 1

Given that \(X = \frac{1}{2}\) we are left with Y = 1

And yes \(\sqrt{Y^2} = |Y|\); and therefore 2 solutions for Y.

But why are you concerned with it for this question? I don't get that.

Also according to me the answer should be "D" not "B".
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 March 2025
Posts: 100,064
Own Kudos:
710,494
 [2]
Given Kudos: 92,683
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 100,064
Kudos: 710,494
 [2]
If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x 10 Oct 2013, 01:07
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
pradeepss
If x = 1/2, is y equal to 1?

(1) y^2(x + 1/2) = 1
(2) y(2x - 1) = 2x - y

Show Spoiler
why is GMAT so biased on sqr(y) = 1. I mean, why sqroot(y) not equal to 1, instead it is + or - 1? for GMAT \sqrt{1} = 1

NOTE: edited the first statement.

If x = 1/2, is y equal to 1?

(1) y^2(x + 1/2) = 1 --> substitute: \(y^2=1\) --> \(y=-1\) or \(y=1\). Not sufficient.

(2) y(2x - 1) = 2x - y --> substitute: \(0=1-y\) --> \(y=1\). Sufficient.

Answer: B.

Hope it's clear.

P.S. Please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html Pay attention to the rules 3 and 5. Thank you.
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 36,683
Own Kudos:
963
Posts: 36,683
Kudos: 963
If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x 27 Nov 2024, 01:44
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.
Moderator:
Bunuel
Math Expert
100064 posts