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

 It is currently 18 May 2013, 19:31

# Divisor Problem

Author Message
TAGS:
Director
Joined: 10 Feb 2006
Posts: 670
Followers: 1

Kudos [?]: 11 [0], given: 0

Divisor Problem [#permalink]  26 May 2006, 20:05

241. If the integer n has exactly three positive divisors, including 1 and n, how many positive divisors does n^2 have?

a 4
b.5
c.6
d.8
e.9
_________________

GMAT the final frontie!!!.

Director
Joined: 10 Feb 2006
Posts: 670
Followers: 1

Kudos [?]: 11 [0], given: 0

_________________

GMAT the final frontie!!!.

Intern
Joined: 05 Apr 2006
Posts: 36
Followers: 0

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

the number of divisors would be 5
the number has to be square of a prime number , for it to have 3 divisors.
the divisors for n ^ 2
1, root(n) , n , n^1.5 , n ^2
VP
Joined: 14 May 2006
Posts: 1421
Followers: 4

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

I would just take a number with 3 divisors, say

n=4 (divisors: 1, 2, 4)
n^2=16 (divisors: 1, 2, 4, 8, 16), so 5 divisors!

also square of an integer has odd number of divisors, whereas even number of divisors tells us that such number doesn't have a square. Based on that it could not be A, C or D
Director
Joined: 10 Oct 2005
Posts: 533
Location: US
Followers: 1

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

5 --- Suppose n = 9 then n sqre = 81
which has 1, 3, 9, 27, and 81 as divisor
Manager
Joined: 11 Oct 2005
Posts: 96
Followers: 1

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

I got 5 as well...pick a number with 3 divisors and square it
Similar topics Replies Last post
Similar
Topics:
Ps: divisor 7 13 Jun 2006, 23:04
divisors 3 28 May 2009, 09:52
Divisor 1 13 Aug 2009, 07:36
Divisors 2 31 Mar 2010, 06:35
2 Divisors 5 22 Apr 2010, 11:28
Display posts from previous: Sort by