• Award-winning private GMAT tutoring
Register now and save up to $200 Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • Free Veritas GMAT Class Experience Lesson 1 Live Free Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Free Practice Test & Review How would you score if you took the GMAT Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • FREE GMAT Exam Know how you'd score today for$0

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

## OG2015 PS In the rectangular solid

tagged by: Brent@GMATPrepNow

This topic has 1 expert reply and 0 member replies
lionsshare Senior | Next Rank: 100 Posts
Joined
09 Aug 2017
Posted:
62 messages

#### OG2015 PS In the rectangular solid

Wed Sep 13, 2017 3:18 am

In the rectangular solid above, the three sides shown have areas 12, 15, and 20, respectively. What is the volume of the solid?

(A) 60
(B) 120
(C) 450
(D) 1,800
(E) 3,600

OA: A

Experts, please share an approach in solving this problem. Thank you.

### GMAT/MBA Expert

Brent@GMATPrepNow GMAT Instructor
Joined
08 Dec 2008
Posted:
11754 messages
Followed by:
1232 members
5254
GMAT Score:
770
Wed Sep 13, 2017 7:32 am
lionsshare wrote:

In the rectangular solid above, the three sides shown have areas 12, 15, and 20, respectively. What is the volume of the solid?

(A) 60
(B) 120
(C) 450
(D) 1,800
(E) 3,600

OA: A
Let the dimensions (length, width and height) of the box be x, y and z
Volume = (length)(width)(height) = xyz
So, our GOAL is to find the value of xyz

The three sides shown have areas 12, 15, and 20, respectively
If one (rectangular) side has area 12, then we can say that xy = 12
If one (rectangular) side has area 15, then we can say that xz = 15
If one (rectangular) side has area 20, then we can say that yz = 20
[notice that we've accounted for all 3 dimensions]

Now, we'll apply the following property: If a = j, and b = k and c = l , then abc = jkl

So, we can write: (xy)(xz)(yz) = (12)(15)(20)
Simplify: x²y²z² = 3600
Rewrite left side as: (xyz)² = 3600
Take the square root of both sides to get: xyz = 60

So, the volume = 60

Cheers,
Brent

_________________
Brent Hanneson – Creator of GMATPrepNow.com
Use our video course along with

Check out the online reviews of our course
Come see all of our free resources

GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!

### Top First Responders*

1 GMATGuruNY 109 first replies
2 Brent@GMATPrepNow 44 first replies
3 Rich.C@EMPOWERgma... 37 first replies
4 Jay@ManhattanReview 25 first replies
5 Scott@TargetTestPrep 11 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

### Most Active Experts

1 GMATGuruNY

The Princeton Review Teacher

159 posts
2 Brent@GMATPrepNow

GMAT Prep Now Teacher

134 posts
3 Scott@TargetTestPrep

Target Test Prep

103 posts
4 Jeff@TargetTestPrep

Target Test Prep

94 posts
5 Rich.C@EMPOWERgma...

EMPOWERgmat

88 posts
See More Top Beat The GMAT Experts