It is currently 18 Jun 2019, 17:06
My Tests

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

a is the product of 3 and the square root of 2, b is the

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
GRE Prep Club Legend
GRE Prep Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4810
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 118

Kudos [?]: 1897 [0], given: 397

a is the product of 3 and the square root of 2, b is the [#permalink] New post 09 Nov 2016, 15:30
Expert's post
00:00

Question Stats:

60% (03:09) correct 40% (03:10) wrong based on 10 sessions
a is the product of 3 and the square root of 2, b is the product of 2 and the square root of 3, and c is the product of 2 and the square root of 6. If x is the square of the sum of a and b, y is the product of 6 and the difference of 5 and c, and z is the product of 2 squared and 3 squared, what is \(\frac{xy}{z}\)?


A. \(1\)
B. \(30 - 12\sqrt{6}\)
C. \(36\)
D. \(30 + 12\sqrt{6}\)
E. \(64\)

Drill 3
Question: 11
Page: 292
[Reveal] Spoiler: OA

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

GRE Prep Club Legend
GRE Prep Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4810
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 118

Kudos [?]: 1897 [0], given: 397

Re: a is the product of 3 and the square root of 2, b is the [#permalink] New post 09 Nov 2016, 15:37
Expert's post
Explanation


Let’s translate this question, one step at a time.

a= \(3\sqrt{2}\), b = \(2\sqrt{3}\) and c= \(2\sqrt{6}\)

x = \((3\sqrt{2}+ 2\sqrt{3})^2\)
= \((3\sqrt{2}+ 2\sqrt{3})(3\sqrt{2}+ 2\sqrt{3})\)

= \(30+12\sqrt{6}\)

y = \(6(5 - 2\sqrt{6})\)=\(30-12\sqrt{6}\)

z = \(2^2*3^2\) =\(36\).

\(\frac{xy}{z}\)=\((30-12\sqrt{6})(30+12\sqrt{6})\frac{1}{36}\) = 1

Hence option A is correct.

Did you recognize the common quadratics? The product of x and y in the last chunk of the question contains one that could save you that intermediary step: \((x + y)(x - y) = x^2 - y^2\). Of course, it doesn’t take too much longer to write out the math.
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Intern
Intern
Joined: 23 Jun 2017
Posts: 1
Followers: 0

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

Re: a is the product of 3 and the square root of 2, b is the [#permalink] New post 23 Jun 2017, 13:36
You said x = 3 + 12*sqrt(6). This is not correct.

x = (3*sqrt(2)+2*sqrt(3))^2 = 30 + 12*sqrt(6).
GRE Prep Club Legend
GRE Prep Club Legend
User avatar
Joined: 07 Jun 2014
Posts: 4810
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 118

Kudos [?]: 1897 [0], given: 397

Re: a is the product of 3 and the square root of 2, b is the [#permalink] New post 24 Jun 2017, 00:12
Expert's post
asdfasdfasdf wrote:
You said x = 3 + 12*sqrt(6). This is not correct.

x = (3*sqrt(2)+2*sqrt(3))^2 = 30 + 12*sqrt(6).


Thanks for pointing out!
It was a typo
_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

Re: a is the product of 3 and the square root of 2, b is the   [#permalink] 24 Jun 2017, 00:12
Display posts from previous: Sort by

a is the product of 3 and the square root of 2, b is the

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.