Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 05 Jul 2015, 13:09

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If b is an integer, is sq(a^2+b^2) an integer? (1) a2 + b2

Author Message
TAGS:
Manager
Joined: 10 Feb 2011
Posts: 115
Followers: 1

Kudos [?]: 88 [0], given: 10

If b is an integer, is sq(a^2+b^2) an integer? (1) a2 + b2 [#permalink]  26 Feb 2011, 15:45
00:00

Difficulty:

35% (medium)

Question Stats:

76% (01:34) correct 24% (00:47) wrong based on 29 sessions
If b is an integer, is sq(a^2+b^2) an integer?

(1) a2 + b2 is an integer.
(2) a^2 – 3b^2 = 0
[Reveal] Spoiler: OA
Math Expert
Joined: 02 Sep 2009
Posts: 28286
Followers: 4479

Kudos [?]: 45291 [1] , given: 6647

Re: . If b is an integer, is sq(a^2+b^2) an integer? (1) a2 + b [#permalink]  26 Feb 2011, 15:55
1
KUDOS
Expert's post
banksy wrote:
If b is an integer, is sq(a^2+b^2) an integer?
(1) a2 + b2 is an integer.
(2) a^2 – 3b^2 = 0

If b is an integer, is sqrt(a^2+b^2) an integer?

(1) a^2 + b^2 is an integer. Clearly insufficient: if a^2 + b^2 is a perfect square, say 4, then the answer is YES but if a^2 + b^2 is NOT a perfect square, say 5, then the answer is NO. Not sufficient.

(2) a^2 – 3b^2 = 0 --> $$a^2=3b^2$$ --> $$\sqrt{a^2+b^2}=\sqrt{3b^2+b^2}=\sqrt{4b^2}=2|b|=integer$$. Sufficient.

_________________
Re: . If b is an integer, is sq(a^2+b^2) an integer? (1) a2 + b   [#permalink] 26 Feb 2011, 15:55
Similar topics Replies Last post
Similar
Topics:
1 If a, b, and c are integers and abc ≠ 0, is a^2 – b^2 7 26 Mar 2013, 00:52
1 If a and b are positive integers, is a^2 + b^2 divisible by 4 11 May 2009, 13:45
If A & B are positive integers, is a^2 + b^2 divisible 4 15 Nov 2007, 01:53
if A and B are positive integers, is $$a^2 + b^2$$ divisable 15 03 Aug 2007, 06:42
If b is an integer, is sqr root (a^2 + b^2) an integer? 1) 7 15 Apr 2006, 19:18
Display posts from previous: Sort by