|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
30 Nov 2017, 23:50
Kudos
Bookmarks
A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
77% (01:47) correct
23%
(01:59)
wrong
based on 83
sessions
History
Date
Time
Result
Not Attempted Yet
What is the length, in centimeters, of an edge of a cube whose surface area is k square centimeters and whose volume is k/2 cubic centimeters?
(A) 3
(B) 6
(C) 9
(D) 12
(E) 36
(A) 3
(B) 6
(C) 9
(D) 12
(E) 36
01 Dec 2017, 10:39
Kudos
Bookmarks
Bunuel
Volume of cube =\(\frac{k}{2}\) \(cm^3\)
Surface area of cube = \(6s^2 = k\) \(cm^2\)
Surface area to find side in terms of \(k\)
\(6s^2 = k\)
\(s^2 = \frac{k}{6}\)
\(s = \frac{\sqrt{k}}{\sqrt{6}}\)
Volume to find numeric value of \(k\)
Volume =\(\frac{k}{2}\) \(cm^3\)
\((\frac{\sqrt{k}}{\sqrt{6}})^3 = \frac{k}{2}\)
\(\sqrt{k} * \sqrt{k} * \sqrt{k} = k\sqrt{k}\)
\(\sqrt{6} * \sqrt{6} * \sqrt{6} = 6\sqrt{6}\)
\(\frac{k\sqrt{k}}{6\sqrt{6}} = \frac{k}{2}\)
\(2(k)\sqrt{k} = (k)6\sqrt{6}\)
\(\sqrt{k} = 3\sqrt{6}\)
\((\sqrt{k})^2 = (3\sqrt{6})^2\)
\(k = 54\)
Surface area to find side length of cube
Surface area of cube = \(6s^2 = k\) \(cm^2\)
\(6s^2 = 54\)
\(s^2 = 9\)
\(s = 3\) \(cm\)
I think Answer A
01 Dec 2017, 11:46
Kudos
Bookmarks
Bunuel
\(6a^2 = k\)
\(a^3 =\frac{k}{2}\)
Lets get a commen power 6
\(6^3 * a^6 = k^3\)
\(a^6 = \frac{k^2}{4}\)
\(6^3 * \frac{k^2}{4} = k^3\)
\(\frac{6^3}{4} = k\)
\(54 = k\)
\(6a^2 = 54\)
\(a^2 = 9 => 3\)
The answer is A
