It is currently 26 Mar 2019, 04:40

### 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

# GRE Arithmetic If x is positive and -x < y < 0

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Intern
Joined: 29 Sep 2015
Posts: 24
Followers: 3

Kudos [?]: 22 [1] , given: 0

GRE Arithmetic If x is positive and -x < y < 0 [#permalink]  30 Nov 2015, 07:44
1
This post received
KUDOS
Expert's post
00:00

Question Stats:

90% (00:35) correct 9% (00:58) wrong based on 11 sessions
If $$x$$ is positive and $$-x < y < 0$$, then which of the following must be negative?

A. $$(x + y)^2$$
B. $$(x - y)^2$$
C. $$(y - x)^2$$
D. $$x^2 - y^2$$
E. $$y^2 - x^2$$
[Reveal] Spoiler: OA

_________________

Ryan Born, Senior GRE Instructor, PowerScore Test Prep
Free GRE 101 Webinar, September 26 @ 8pm Eastern Time.
Reserve your spot! https://www.powerscore.com/freeseminars/gre/

Intern
Joined: 29 Sep 2015
Posts: 24
Followers: 3

Kudos [?]: 22 [1] , given: 0

Re: GRE Arithmetic If x is positive and -x < y < 0 [#permalink]  30 Nov 2015, 07:45
1
This post received
KUDOS
Expert's post
[Reveal] Spoiler: Solution
Step 1: Rule out products of squaring. The square of any real number (meaning any value on the number line) cannot be negative. Since squaring is the final operation in (A), (B), and (C), those answer choices must work out to either zero or some positive value.

A. $$(x + y)^2$$
B. $$(x - y)^2$$
C. $$(y - x)^2$$

Step 2: Assign values to x and y if you're unsure whether $$x^2$$ or $$y^2$$ is bigger. Neither x nor y is equal to zero, so both $$x^2$$ and $$y^2$$ are positive. If $$x^2 > y^2$$, then (E) must be correct, since a smaller positive minus a larger positive must equal a negative.

Let $$x = 2$$ and $$y = -1$$.
D. $$2^2 - (-1)^2 = 4 - 1 = 3$$
E. $$(-1)^2 - 2^2 = 1 - 4 = -3$$

_________________

Ryan Born, Senior GRE Instructor, PowerScore Test Prep
Free GRE 101 Webinar, September 26 @ 8pm Eastern Time.
Reserve your spot! https://www.powerscore.com/freeseminars/gre/

Manager
Joined: 06 Jun 2018
Posts: 94
Followers: 0

Kudos [?]: 58 [0], given: 0

Re: GRE Arithmetic If x is positive and -x < y < 0 [#permalink]  17 Jul 2018, 15:20
RBornPowerScore wrote:
If $$x$$ is positive and $$-x < y < 0$$, then which of the following must be negative?

A. $$(x + y)^2$$
B. $$(x - y)^2$$
C. $$(y - x)^2$$
D. $$x^2 - y^2$$
E. $$y^2 - x^2$$

Amazing question.

Note : x is a positive number but negative x is greater than y, which is also negative. So, we can conclude that positive x is greater that the value of y.

Suppose ,

x = 10 and negative x = -10.

y = -5

Option E:

$$y^2 - x^2$$ = (-5)^2 - ( 10)^2

= 25 -100

= -75

The best answer is E.
Re: GRE Arithmetic If x is positive and -x < y < 0   [#permalink] 17 Jul 2018, 15:20
Display posts from previous: Sort by

# GRE Arithmetic If x is positive and -x < y < 0

 Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.