It is currently 17 Aug 2019, 18:39

### 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

# A perfect square is a positive integer which when square roo

Author Message
TAGS:
Founder
Joined: 18 Apr 2015
Posts: 7695
Followers: 142

Kudos [?]: 1585 [0], given: 6981

A perfect square is a positive integer which when square roo [#permalink]  16 Apr 2019, 00:41
Expert's post
00:00

Question Stats:

42% (00:14) correct 57% (00:00) wrong based on 7 sessions
A perfect square is a positive integer which when square rooted results in an integer. If $$N = 3^4 * 5^3 * 7$$, then what is the biggest perfect square that is a factor of $$N$$?

(A) $$3^2$$

(B) $$5^2$$

(C) $$9^2$$

(D) $$(9 * 5)^2$$

(E) $$(3 * 5 * 7)^2$$
[Reveal] Spoiler: OA

_________________
Director
Joined: 07 Jan 2018
Posts: 669
Followers: 8

Kudos [?]: 641 [1] , given: 88

Re: A perfect square is a positive integer which when square roo [#permalink]  21 Apr 2019, 05:19
1
KUDOS
First notice that all the options are a perfect square. However we need the biggest among them. It can be seen easily that A<B<C<D therefore we can eliminate A, B and C. Now among D and E, D is bigger so it is the answer. Since both are square of some numbers in the bracket we can only compare the expression inside the bracket
_________________

This is my response to the question and may be incorrect. Feel free to rectify any mistakes

Manager
Joined: 22 Jun 2019
Posts: 106
Followers: 0

Kudos [?]: 12 [0], given: 34

Re: A perfect square is a positive integer which when square roo [#permalink]  06 Aug 2019, 18:41
Carcass wrote:
A perfect square is a positive integer which when square rooted results in an integer. If $$N = 3^4 * 5^3 * 7$$, then what is the biggest perfect square that is a factor of $$N$$?

(A) $$3^2$$

(B) $$5^2$$

(C) $$9^2$$

(D) $$(9 * 5)^2$$

(E) $$(3 * 5 * 7)^2$$

need explanation

Last edited by huda on 07 Aug 2019, 01:47, edited 6 times in total.
Founder
Joined: 18 Apr 2015
Posts: 7695
Followers: 142

Kudos [?]: 1585 [0], given: 6981

Re: A perfect square is a positive integer which when square roo [#permalink]  14 Aug 2019, 02:27
Expert's post
Precisely, what did you not get sir in the explanation above ??

Regards
_________________
Manager
Joined: 22 Jun 2019
Posts: 106
Followers: 0

Kudos [?]: 12 [1] , given: 34

Re: A perfect square is a positive integer which when square roo [#permalink]  15 Aug 2019, 11:28
1
KUDOS
Carcass wrote:
Precisely, what did you not get sir in the explanation above ??

Regards

later I got it but forgot to mention. Thanks for the concern.
Intern
Joined: 07 Feb 2019
Posts: 32
Followers: 0

Kudos [?]: 10 [1] , given: 1

Re: A perfect square is a positive integer which when square roo [#permalink]  16 Aug 2019, 03:00
1
KUDOS
Convert the options to prime factors

(A) $$3^2$$

(B) $$5^2$$

(C) $$3^4$$

(D) $$3^4 * 5^2$$

(E) $$(3 * 5 * 7)^2$$

D is clearly the biggest factor of N
Re: A perfect square is a positive integer which when square roo   [#permalink] 16 Aug 2019, 03:00
Display posts from previous: Sort by