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

 It is currently 11 Feb 2016, 18:05

### 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 x is divisible by 42. Which of the following numbers is d

Author Message
TAGS:
Manager
Joined: 24 Jan 2010
Posts: 164
Location: India
Schools: ISB
Followers: 2

Kudos [?]: 40 [0], given: 14

If x is divisible by 42. Which of the following numbers is d [#permalink]  26 Jun 2010, 02:20
00:00

Difficulty:

(N/A)

Question Stats:

20% (00:00) correct 80% (01:20) wrong based on 5 sessions
If x is divisible by 42. Which of the following numbers is definitely a factor of x2? (Choose all that apply.)

A. 63
B. 33
C. 36
D. 8
[Reveal] Spoiler: OA

_________________

_________________
If you like my post, consider giving me a kudos. THANKS!

Manager
Joined: 05 Mar 2010
Posts: 221
Followers: 1

Kudos [?]: 27 [0], given: 8

Re: Number System- Divisibility [#permalink]  26 Jun 2010, 03:17
Is it x*2 or x^2

If x^2 then my answer is C

6 is a factor of 42 ( x is a multiple of 42) then 6 will repeat in every multiple of 42 (84, 126, .......) so 36 will definately be the factor
_________________

Success is my Destiny

Math Expert
Joined: 02 Sep 2009
Posts: 31297
Followers: 5359

Kudos [?]: 62441 [2] , given: 9455

Re: Number System- Divisibility [#permalink]  26 Jun 2010, 03:25
2
KUDOS
Expert's post
If x is divisible by 42. Which of the following numbers is definitely a factor of x2? (Choose
all that apply.)
a) 63 b) 33 c) 36 d) 8

It will be helpful if group can explain the answer as well.

Given: $$x=42k=2*3*7*k$$ (where $$k$$ is an integer) --> $$x^2=2^2*3^3*7^2*k^2$$.

A. $$63=3^2*7$$ is a factor of $$x^2$$;

B. $$33=3*11$$ may NOT be a factor of $$x^2$$ (we don't know whether 11 is a factor $$x^2$$);

C. $$36=2^2*3^2$$ is a factor of $$x^2$$;

D. $$8=2^3$$ may NOT be a factor of $$x^2$$ ($$2^2=4$$ is a factor of $$x^2$$, but we need one more 2 and we don't know whether unknown multiple, $$k^2$$, contains it or not).

_________________
Manager
Joined: 24 Jan 2010
Posts: 164
Location: India
Schools: ISB
Followers: 2

Kudos [?]: 40 [0], given: 14

Re: Number System- Divisibility [#permalink]  26 Jun 2010, 08:47
Bunuel wrote:
If x is divisible by 42. Which of the following numbers is definitely a factor of x2? (Choose
all that apply.)
a) 63 b) 33 c) 36 d) 8

It will be helpful if group can explain the answer as well.

Given: $$x=42k=2*3*7*k$$ (where $$k$$ is an integer) --> $$x^2=2^2*3^3*7^2*k^2$$.

A. $$63=3^2*7$$ is a factor of $$x^2$$;

B. $$33=3*11$$ may NOT be a factor of $$x^2$$ (we don't know whether 11 is a factor $$x^2$$);

C. $$36=2^2*3^2$$ is a factor of $$x^2$$;

D. $$8=2^3$$ may NOT be a factor of $$x^2$$ ($$2^2=4$$ is a factor of $$x^2$$, but we need one more 2 and we don't know whether unknown multiple, $$k^2$$, contains it or not).

Thanks for the solution

+1 Kudos
_________________

_________________
If you like my post, consider giving me a kudos. THANKS!

Re: Number System- Divisibility   [#permalink] 26 Jun 2010, 08:47
Similar topics Replies Last post
Similar
Topics:
The integer x is divisible by both 8 and 14. Which of the following 2 03 Dec 2015, 05:26
If x/y = c/d and d/c = b/a, which of the following must be true? 6 18 Oct 2015, 11:57
5 If x and y are prime numbers, which of the following CANNOT 8 06 Feb 2012, 03:14
17 If x is a number such that –2 ≤ x ≤ 2 which of the following 22 10 Apr 2011, 20:20
9 If x is a number such that –2 ≤ x ≤ 2, which of the following has the 5 12 Jan 2007, 22:44
Display posts from previous: Sort by