|
Author |
Message |
|
TAGS:
|
|
|
Manager
Joined: 11 May 2004
Posts: 51
Location: USA
Followers: 0
Kudos [?]:
1
[0], given: 0
|
What is the value of the integer n 1. n(n+2)=15 2. [#permalink]
 14 Jun 2006, 20:11
What is the value of the integer n
1. n(n+2)=15
2. (n+2)^n=125
THe answer key says C these answers are sometimes wrong, so i dunno, anyone know why its C i mean im wondering if its B i know its not A because -7 and -3 would work, but im wondering if its B. Anyone know? Nevermind i get it its C bcause u get 2 soultiuons on A and only the soulation of one works on teh 2nd one hence C, what a dummie question i put on here, sorry guys.
|
|
|
|
|
|
|
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5134
Location: Singapore
Followers: 9
Kudos [?]:
87
[0], given: 0
|
St1:
n^2+2n-15 = 0
(n-3)(n+5) = 0
n = 3, n = -5 ---> Insufficient.
St2:
(n+2)^n = 125
n must be 3, since (3+2)^3 = 125....
I can't see why it's C. Should be B.
|
|
|
|
|
|
SVP
Joined: 30 Mar 2006
Posts: 1744
Followers: 1
Kudos [?]:
12
[0], given: 0
|
1) n(n+2) = 15
Hence n can be -5 or 3
Not suff
2) (n+2)^n = 125
(n+2)^n = 5^3
Only 3 satisfies N hence B is suff.
|
|
|
|
|
|
Director
Joined: 06 May 2006
Posts: 791
Followers: 3
Kudos [?]:
7
[0], given: 0
|
Should be B.
(n +2)^n = 125 has only one answer, I reckon, and that is 3. The first expression can evaluate to -5 or 3.
|
|
|
|
|
|
Manager
Joined: 11 May 2004
Posts: 51
Location: USA
Followers: 0
Kudos [?]:
1
[0], given: 0
|
official answer is B i checked.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
close
