Last visit was: 24 Nov 2024, 14:04 It is currently 24 Nov 2024, 14:04

Close

GRE Prep 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 GRE 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
Verbal Expert
Joined: 18 Apr 2015
Posts: 30017
Own Kudos [?]: 36379 [3]
Given Kudos: 25928
Send PM
Retired Moderator
Joined: 09 Jan 2021
Posts: 576
Own Kudos [?]: 846 [0]
Given Kudos: 194
GRE 1: Q167 V156
GPA: 4
WE:Analyst (Investment Banking)
Send PM
Manager
Manager
Joined: 22 Sep 2020
Posts: 74
Own Kudos [?]: 65 [0]
Given Kudos: 97
Send PM
Verbal Expert
Joined: 18 Apr 2015
Posts: 30017
Own Kudos [?]: 36379 [0]
Given Kudos: 25928
Send PM
x>0 and 0<x^2<1 [#permalink]
Expert Reply
The question is a bit tricky. However, it could be solved without picking numbers but just with logic

Now, x is positive and squared is a fraction between 0 and 1

But if a fraction squared is between 0 and 1 that means the original fraction - notice how is mentioned that x>0 at the origin - is still between zero and one but is bigger than the squared one

\(x^2<x\)

For example \(x=\frac{1}{2}\)

\(x^2=\frac{1}{4}
\)

\(\frac{1}{4}<\frac{1}{2}\)

So \(1-x^2>1-x
\)

I fixed the OA because the book reported D as OA but indeed is A
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Own Kudos [?]: 3224 [1]
Given Kudos: 172
Location: India
WE:Education (Education)
Send PM
Re: x>0 and 0<x^2<1 [#permalink]
1
Carcass wrote:
\(x>0\) and \(0<x^2<1\)


Quantity A
Quantity B
\(1-x^2\)
\(1-x\)




A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.


x must be a positive fraction!

Col. A: \(1-x^2\)
Col. B: \(1-x\)

Adding \(x^2\) and \(x\) to both sides;

Col. A: \(1 + x\)
Col. B: \(1 + x^2\)

Subtracting \(1\) from both sides;

Col. A: \(x\)
Col. B: \(x^2\)

Dividing both sides by \(x\);

Col. A: \(1\)
Col. B: \(x\)

Hence, option A
Intern
Intern
Joined: 17 Nov 2020
Posts: 7
Own Kudos [?]: 1 [0]
Given Kudos: 12
Send PM
Re: x>0 and 0<x^2<1 [#permalink]
Hello - Couldnt we also just factor A to the following:

(1+x)(1-x)

Then divide each A & B by (1-x) leaving us:

A: 1+x
B: 0

We know X is positive, so A is greater. Is this allowed?
Verbal Expert
Joined: 18 Apr 2015
Posts: 30017
Own Kudos [?]: 36379 [0]
Given Kudos: 25928
Send PM
Re: x>0 and 0<x^2<1 [#permalink]
Expert Reply
PTMBA23 wrote:
Hello - Couldnt we also just factor A to the following:

(1+x)(1-x)

Then divide each A & B by (1-x) leaving us:

A: 1+x
B: 0

We know X is positive, so A is greater. Is this allowed?


yes this is another and faster approach
Retired Moderator
Joined: 09 Jan 2021
Posts: 576
Own Kudos [?]: 846 [1]
Given Kudos: 194
GRE 1: Q167 V156
GPA: 4
WE:Analyst (Investment Banking)
Send PM
Re: x>0 and 0<x^2<1 [#permalink]
1
Hi nurakib!

Apologies! Missed this one! Updated the explanation!


Kind regards

Posted from my mobile device
User avatar
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 5046
Own Kudos [?]: 75 [0]
Given Kudos: 0
Send PM
Re: x>0 and 0<x^2<1 [#permalink]
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep 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.
Prep Club for GRE Bot
Re: x>0 and 0<x^2<1 [#permalink]
Moderators:
GRE Instructor
84 posts
GRE Forum Moderator
37 posts
Moderator
1111 posts
GRE Instructor
234 posts

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