GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 22 Oct 2019, 20:20

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

If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Manager
Manager
User avatar
Status: Please do not forget to give kudos if you like my post
Joined: 19 Sep 2008
Posts: 86
Location: United States (CA)
GMAT ToolKit User
If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x  [#permalink]

Show Tags

New post Updated on: 05 Jun 2019, 05:23
3
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

82% (01:05) correct 18% (01:04) wrong based on 147 sessions

HideShow timer Statistics

If \(x = \frac{1}{2}\), is y equal to 1?


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

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

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

_________________

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.
Manager
Manager
avatar
B
Joined: 29 Aug 2013
Posts: 69
Location: United States
Concentration: Finance, International Business
GMAT 1: 590 Q41 V29
GMAT 2: 540 Q44 V20
GPA: 3.5
WE: Programming (Computer Software)
Re: If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x  [#permalink]

Show Tags

New post 09 Oct 2013, 22:12
pradeepss wrote:
if X = 1/2, is Y equal to 1?

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

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.

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

For this question my Answer would be D.

Consider Kudos if the post helps. :-D
Manager
Manager
User avatar
Status: Please do not forget to give kudos if you like my post
Joined: 19 Sep 2008
Posts: 86
Location: United States (CA)
GMAT ToolKit User
Re: If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x  [#permalink]

Show Tags

New post 09 Oct 2013, 22:49
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.
_________________
Manager
Manager
avatar
B
Joined: 29 Aug 2013
Posts: 69
Location: United States
Concentration: Finance, International Business
GMAT 1: 590 Q41 V29
GMAT 2: 540 Q44 V20
GPA: 3.5
WE: Programming (Computer Software)
Re: If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x  [#permalink]

Show Tags

New post 10 Oct 2013, 00:44
pradeepss wrote:
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".
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58427
Re: If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x  [#permalink]

Show Tags

New post 10 Oct 2013, 01:07
1
pradeepss wrote:
If x = 1/2, is y equal to 1?

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

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.
_________________
Target Test Prep Representative
User avatar
D
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8137
Location: United States (CA)
Re: If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x  [#permalink]

Show Tags

New post 11 Oct 2016, 16:56
2
1
pradeepss wrote:
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
_________________

Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
TTP - Target Test Prep Logo
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13412
Re: If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x  [#permalink]

Show Tags

New post 11 Jun 2019, 21:20
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.
_________________
GMAT Club Bot
Re: If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x   [#permalink] 11 Jun 2019, 21:20
Display posts from previous: Sort by

If x = 1/2, is y equal to 1? (1) y^2(x + 1/2) = 1 (2) y(2x - 1) = 2x

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne