Problem Solving - Roots question - The Beat The GMAT Forum - Expert GMAT Help & MBA Admissions Advice

Problem Solving - Roots question

Expert replies

MOARQUESTIONS: Junior | Next Rank: 30 Posts; Posts: 10; Joined: Thu Oct 13, 2011 8:30 pm

by MOARQUESTIONS » Wed Oct 19, 2011 1:41 pm

I didn't understand the answer to this question. Hopefully one of you GMAT wizards can give me clarity on it.

Roots are kind of hard to illustrate on boards so I used arrows to space it.

3sqrt(3) -->4sqrt(3)
________ X ________

sqrt(2) --->3

A) 3
B) 6sqrt(2)
C) 12
D) 12sqrt(2)
E) 36

[spoiler]ANSWER : B[/spoiler]

Attachments

Last edited by MOARQUESTIONS on Wed Oct 19, 2011 2:36 pm, edited 1 time in total.

Like this post

Source: Beat The GMAT — Problem Solving | Wed Oct 19, 2011 1:41 pm

neelgandham: Community Manager; Posts: 1060; Joined: Fri May 13, 2011 6:46 amFollowed by: 52 members; Location: Utrecht, The Netherlands; Thanked: 318 times

by neelgandham » Wed Oct 19, 2011 2:15 pm

Do you mind re-framing ? Never understood a bit !

Anil Gandham
Welcome to BEATtheGMAT | Photography | Getting Started | BTG Community rules | MBA Watch
Check out GMAT Prep Now's online course at https://www.gmatprepnow.com/

Like this post

GMATGuruNY: GMAT Instructor; Posts: 15539; Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members; Location: New York, NY; Thanked: 13060 times; GMAT Score:790

by GMATGuruNY » Wed Oct 19, 2011 2:37 pm

MOARQUESTIONS wrote:I didn't understand the answer to this question. Hopefully one of you GMAT wizards can give me clarity on it.

Roots are kind of hard to illustrate on boards so I used arrows to space it.

3sqrt(3) -->4sqrt(3)
________ X ________

sqrt(2) --->3

A) 3
B) 6sqrt(2)
C) 12
D) 12sqrt(2)
E) 36

[spoiler]ANSWER : B[/spoiler]

Combining the two fractions into one, we get:

= (3âˆš3)(4âˆš3) / (âˆš2)*3 -- Divide each side by 3.

= 4 * (âˆš3)(âˆš3) / (âˆš2) -- Multiply (âˆš3)(âˆš3)=3.

=4*3 / âˆš2 -- Multiply 4*3.

=12 * âˆš2 / (âˆš2*âˆš2) -- To eliminate âˆš2 from the denominator, multiply by âˆš2/âˆš2.

= 12âˆš2 / 2 -- Divide by 2.

= 6âˆš2.

The correct answer is B.

Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Like this post

MOARQUESTIONS: Junior | Next Rank: 30 Posts; Posts: 10; Joined: Thu Oct 13, 2011 8:30 pm

by MOARQUESTIONS » Wed Oct 19, 2011 2:37 pm

Just got home from the library, decided it was tablet time.

Like this post

MOARQUESTIONS: Junior | Next Rank: 30 Posts; Posts: 10; Joined: Thu Oct 13, 2011 8:30 pm

by MOARQUESTIONS » Fri Oct 21, 2011 12:57 pm

Thanks for the answer, however I just don't understand the first step. I understand how you simplified the subsequent parts, but if you could explain in another way why you divided each side by three and how you got from that to the 2nd step that would be great.

Like this post

GMAT/MBA Expert

Anurag@Gurome: GMAT Instructor; Posts: 3835; Joined: Fri Apr 02, 2010 10:00 pmFollowed by: 523 members; Location: Milpitas, CA; Thanked: 1854 times; GMAT Score:770

by Anurag@Gurome » Fri Oct 21, 2011 9:45 pm

MOARQUESTIONS wrote:I understand how you simplified the subsequent parts, but if you could explain in another way why you divided each side by three and how you got from that to the 2nd step that would be great.

If you can't view the above image go to this link : https://postimage.org/image/2zptb1wbo/

Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/

Like this post

MOARQUESTIONS: Junior | Next Rank: 30 Posts; Posts: 10; Joined: Thu Oct 13, 2011 8:30 pm

by MOARQUESTIONS » Sat Oct 22, 2011 12:46 pm

Thanks! That was a perfectly illustrated answer!

Like this post

TrueGritMick: Newbie | Next Rank: 10 Posts; Posts: 6; Joined: Sun Oct 09, 2011 12:11 am; Thanked: 1 times

by TrueGritMick » Sat Oct 22, 2011 1:24 pm

My key to looking at this question was basic properties of fractions - to multiply two fractions, you just multiply numerator with numerator and denominator with denominator, straight across.

From there, its just properties of radicals and simplifying the fraction.

Thanks MOAR and Anurag for posting and answering this question!

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review