It is currently 11 Dec 2017, 12:15

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Does (x + y)² + (x – y)² = 170?

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

Hide Tags

Intern
Intern
avatar
Joined: 28 Apr 2014
Posts: 17

Kudos [?]: 10 [0], given: 4

Does (x + y)² + (x – y)² = 170? [#permalink]

Show Tags

New post 11 Jun 2015, 23:07
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

75% (00:56) correct 25% (01:10) wrong based on 89 sessions

HideShow timer Statistics

Does (x + y)^2 + (x – y)^2 = 170?

(1) x^2 + y^2 = 85
(2) x = y + 1
[Reveal] Spoiler: OA

Kudos [?]: 10 [0], given: 4

Intern
Intern
avatar
Joined: 28 Jan 2013
Posts: 31

Kudos [?]: 58 [0], given: 32

Location: United States
Concentration: General Management, International Business
GPA: 3.1
WE: Information Technology (Consulting)
Re: Does (x + y)² + (x – y)² = 170? [#permalink]

Show Tags

New post 11 Jun 2015, 23:27
zahraf
Does (x + y)² + (x – y)² = 170?

(1) x² + y² = 85

Either x=7,y=6 or x=6,y=7 are the only values that satisfy the above equation.
case i) x=7,y=6
value of (x + y)² + (x – y)² will be 170

case ii) x=6,y=7
value of (x + y)² + (x – y)² will be 170

Sufficient

(2) x = y + 1
for this you can't get the exact values of x and y.

Say
X=7,Y=6
then (x + y)² + (x – y)² will be 170
X=5,Y=4
then (x + y)² + (x – y)² will be 82
so clearly statement 2 is Insufficient

Ans : A

Regards,
Manoj Reddy
Please press +1 kudos if you appreciate this post !!

Kudos [?]: 58 [0], given: 32

Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42544

Kudos [?]: 135256 [1], given: 12679

Re: Does (x + y)² + (x – y)² = 170? [#permalink]

Show Tags

New post 12 Jun 2015, 01:57
1
This post received
KUDOS
Expert's post
zahraf wrote:
Does (x + y)^2 + (x – y)^2 = 170?

(1) x^2 + y^2 = 85
(2) x = y + 1


Does (x + y)^2 + (x – y)^2 = 170?

Does x^2 + 2xy + y^2 + x^2 - 2xy + y^2 = 170?
Does 2x^2 + 2y^2 = 170?
Does x^2 + y^2 = 85?

(1) x^2 + y^2 = 85. Directly answers the question. Sufficient.

(2) x = y + 1. If x = 1 and y = 0, then the answer is NO but if x = 7 and y = 6, then the answer is YES. Not sufficient.

Answer: A.

Hope it's clear.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 135256 [1], given: 12679

Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42544

Kudos [?]: 135256 [1], given: 12679

Re: Does (x + y)² + (x – y)² = 170? [#permalink]

Show Tags

New post 12 Jun 2015, 02:04
1
This post received
KUDOS
Expert's post
ManojReddy wrote:
zahraf
Does (x + y)² + (x – y)² = 170?

(1) x² + y² = 85

Either x=7,y=6 or x=6,y=7 are the only values that satisfy the above equation.
case i) x=7,y=6
value of (x + y)² + (x – y)² will be 170

case ii) x=6,y=7
value of (x + y)² + (x – y)² will be 170

Sufficient

(2) x = y + 1
for this you can't get the exact values of x and y.

Say
X=7,Y=6
then (x + y)² + (x – y)² will be 170
X=5,Y=4
then (x + y)² + (x – y)² will be 82
so clearly statement 2 is Insufficient

Ans : A

Regards,
Manoj Reddy
Please press +1 kudos if you appreciate this post !!


Red text above is not correct.

We are not told that x and y are integers, so x^2 + y^2 = 85 will have infinite number of solutions.

Next, even if we were told that x and y are integers, there still would be more solutions (16 integer solutions):
x = ±9, y = ±2;
x = ±7, y = ±6;
x = ±6, y = ±7;
x = ±2, y = ±9.

Hope it helps.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 135256 [1], given: 12679

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 14937

Kudos [?]: 287 [0], given: 0

Premium Member
Re: Does (x + y)² + (x – y)² = 170? [#permalink]

Show Tags

New post 31 Oct 2017, 16:16
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 Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 287 [0], given: 0

Re: Does (x + y)² + (x – y)² = 170?   [#permalink] 31 Oct 2017, 16:16
Display posts from previous: Sort by

Does (x + y)² + (x – y)² = 170?

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


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.