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100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote ## The areas of three faces of a rectangular solid are 12, 15 a tagged by: Max@Math Revolution ##### This topic has 3 expert replies and 0 member replies ### GMAT/MBA Expert ## The areas of three faces of a rectangular solid are 12, 15 a ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult [GMAT math practice question] The areas of three faces of a rectangular solid are 12, 15 and 20. What is the volume of the rectangular solid? A. 30 B. 60 C. 180 D. 900 E. 3600 _________________ Math Revolution Finish GMAT Quant Section with 10 minutes to spare. The one-and-only Worldâ€™s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy. Only$149 for 3 month Online Course
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Max@Math Revolution wrote:
[GMAT math practice question]

The areas of three faces of a rectangular solid are 12, 15 and 20. What is the volume of the rectangular solid?

A. 30
B. 60
C. 180
D. 900
E. 3600
Let x = the width
Let y = the length
Let z = the height
So, the volume = xyz

Area of one face = 12
We can write: xy = 12

Area of one face = 15
We can write: xz = 15

Area of one face = 20
We can write: yz = 20

Combine to get: (xy)(xz)(yz) = (12)(15)(20)
Simplify: xÂ²yÂ²zÂ² = 3600
Rewrite as: (xyz)Â² = 60Â²
So, xyz = 60
In other words, the volume = 60

Cheers,
Brent

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=>

The volume of the above rectangular solid is xyz and the areas of three of its faces are xy, yz, zx.
We may assume xy = 12, yz = 15 and zx = 20 without loss of generality.
Therefore, (xy)(yz)(zx) = (xyz)^2 = 12*15*20 = 3600 = 60^2
Thus, the volume is xyz = 60.

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Only $149 for 3 month Online Course Free Resources-30 day online access & Diagnostic Test Unlimited Access to over 120 free video lessons-try it yourself Email to : info@mathrevolution.com ### GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 2811 messages Followed by: 18 members Upvotes: 43 Max@Math Revolution wrote: [GMAT math practice question] The areas of three faces of a rectangular solid are 12, 15 and 20. What is the volume of the rectangular solid? A. 30 B. 60 C. 180 D. 900 E. 3600 The dimensions of the rectangular solid must be 3, 4, 5 so that the areas of its three faces could be 3 x 4 = 12, 3 x 5 = 15 and 4 x 5 = 20. So the volume of the solid is 3 x 4 x 5 = 60. Answer: B _________________ Scott Woodbury-Stewart Founder and CEO scott@targettestprep.com See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews • FREE GMAT Exam Know how you'd score today for$0

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