It is currently 05 Dec 2019, 06:30

### 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: 8933
Followers: 178

Kudos [?]: 2106 [0], given: 8289

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

Question Stats:

66% (00:56) correct 33% (00:00) wrong based on 12 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

_________________

Need Practice? 20 Free GRE Quant Tests available for free with 20 Kudos
GRE Prep Club Members of the Month: Each member of the month will get three months free access of GRE Prep Club tests.

Director
Joined: 07 Jan 2018
Posts: 694
Followers: 10

Kudos [?]: 702 [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
Need Practice? 20 Free GRE Quant Tests available for free with 20 Kudos

Senior Manager
Joined: 22 Jun 2019
Posts: 378
Followers: 0

Kudos [?]: 51 [0], given: 133

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: 8933
Followers: 178

Kudos [?]: 2106 [0], given: 8289

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
_________________

Need Practice? 20 Free GRE Quant Tests available for free with 20 Kudos
GRE Prep Club Members of the Month: Each member of the month will get three months free access of GRE Prep Club tests.

Senior Manager
Joined: 22 Jun 2019
Posts: 378
Followers: 0

Kudos [?]: 51 [1] , given: 133

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: 36
Followers: 0

Kudos [?]: 14 [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
Manager
Joined: 18 Jun 2019
Posts: 124
Followers: 0

Kudos [?]: 22 [0], given: 62

Re: A perfect square is a positive integer which when square roo [#permalink]  19 Aug 2019, 08:39
I keep wondering isnt 3*5*7 sq bigger?
Founder
Joined: 18 Apr 2015
Posts: 8933
Followers: 178

Kudos [?]: 2106 [0], given: 8289

Re: A perfect square is a positive integer which when square roo [#permalink]  19 Aug 2019, 10:56
Expert's post
No

Regards
_________________

Need Practice? 20 Free GRE Quant Tests available for free with 20 Kudos
GRE Prep Club Members of the Month: Each member of the month will get three months free access of GRE Prep Club tests.

Re: A perfect square is a positive integer which when square roo   [#permalink] 19 Aug 2019, 10:56
Display posts from previous: Sort by