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

 It is currently 05 May 2015, 07:21

### 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 sqr root (a^2 + b^2) an integer? 1)

Author Message
TAGS:
Intern
Joined: 08 Sep 2005
Posts: 44
Followers: 0

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

If b is an integer, is sqr root (a^2 + b^2) an integer? 1) [#permalink]  15 Apr 2006, 19:18
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
If b is an integer, is sqr root (a^2 + b^2) an integer?

1) a^2 + b^2 is an integer.
2) a^2 - 3b^2 = 0
Manager
Joined: 08 Feb 2006
Posts: 128
Followers: 1

Kudos [?]: 6 [0], given: 0

B for me

1)square root of integer, still don't know if it is an integer or not

2)a^2 -3b^2
= a^2=3b^2

squareroot 3b^2+b^2
= squareroot 4b^2
=2b
Sufficient since b is an integer
VP
Joined: 29 Dec 2005
Posts: 1349
Followers: 7

Kudos [?]: 30 [0], given: 0

jlui4477 wrote:
B for me
1)square root of integer, still don't know if it is an integer or not
2) a^2 -3b^2 = a^2=3b^2

= squareroot 3b^2+b^2
= squareroot 4b^2
= 2b
Sufficient since b is an integer

= squareroot 4b^2 = + or - 2b (but still is an integer)

B.
Manager
Joined: 08 Feb 2006
Posts: 128
Followers: 1

Kudos [?]: 6 [0], given: 0

Thanks for the correction
VP
Joined: 29 Apr 2003
Posts: 1405
Followers: 2

Kudos [?]: 18 [0], given: 0

Another one for B!

A doesnt work!

B:

a^2 + b^2 = a^2 - 3B^2 + 4b^2 = 0 + 4B^2

So sqrt(a^2 + b^2) = 2b! Which is an integer!
Manager
Joined: 20 Nov 2004
Posts: 108
Followers: 0

Kudos [?]: 2 [0], given: 0

Professor wrote:
= squareroot 4b^2 = + or - 2b (but still is an integer)
B.

Professor,

it's true that (+2b)^2 and (-2b)^2 lead to 4b^2, but
the square root of 4b^2 is by definition only +2b.
VP
Joined: 29 Dec 2005
Posts: 1349
Followers: 7

Kudos [?]: 30 [0], given: 0

huuuuuuuuhhhhhhh............

i take back my statement... you are correct........

ccax wrote:
Professor wrote:
= squareroot 4b^2 = + or - 2b (but still is an integer)
B.

Professor,

it's true that (+2b)^2 and (-2b)^2 lead to 4b^2, but
the square root of 4b^2 is by definition only +2b.
Manager
Joined: 27 Mar 2006
Posts: 136
Followers: 1

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

Re: DS [#permalink]  18 Apr 2006, 09:29
john2005 wrote:
If b is an integer, is sqr root (a^2 + b^2) an integer?

1) a^2 + b^2 is an integer.
2) a^2 - 3b^2 = 0

B it is
Re: DS   [#permalink] 18 Apr 2006, 09:29
Similar topics Replies Last post
Similar
Topics:
1 If b is an integer, is sq(a^2+b^2) an integer? (1) a2 + b2 1 26 Feb 2011, 15:45
If a and b are positive integers (a > b), is a^2 - b^2 4 07 Nov 2008, 06:36
If a and b are positive integers (a > b), is a^2 - b^2 1 06 Nov 2008, 03:44
If a and b are positive integers (a > b), is a^2 b^2 11 21 Nov 2007, 02:37
IF a and b are positive integers, is < 1? 1) b = 2a. 2) b 5 12 Oct 2006, 15:45
Display posts from previous: Sort by