Events & Promotions
|
|
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.
Sep 1507:00 PM EDT
-09:00 PM EST
Elite scores are possible when you enroll in a powerful GMAT course, taught live online + 6 months access to TTP OnDemand video courses included! Class starts Tues/Thurs Sept. 15, 2026 - Nov. 15, 2027, 7:00pm-9:00pm EST
Sep 2107:00 PM EDT
-10:00 PM EDT
Boost your GMAT score in less than one month in a live online class + 6 months access to TTP OnDemand video courses included! Class starts Mon, Tues, Wed, Thur, Fri Sept. 21, 2026 - Oct. 9, 2027, 7:00pm-10:00pm EST
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
5%
(low)
Question Stats:
90% (01:33) correct
10%
(02:06)
wrong
based on 71
sessions
History
Date
Time
Result
Not Attempted Yet
A square mirror has exactly half the area of the rectangular wall on which it is hung. If each side of the mirror is 42 inches and the width of the wall is 56 inches, what is the length of the wall, in inches?
(A) 84
(B) 72
(C) 70
(D) 63
(E) 56
(A) 84
(B) 72
(C) 70
(D) 63
(E) 56
MartyTargetTestPrep
Expert
Target Test Prep Representative
Joined: 24 Nov 2014
Last visit: 11 Aug 2023
Posts: 3,471
Status:Chief Curriculum and Content Architect
Affiliations: Target Test Prep
GMAT 1: 800 Q51 V51
Expert reply
GMAT 1: 800 Q51 V51
Posts: 3,471
Turkish
Just to be cute and do this without too many calculations, we could factor 42 into 2 * 3 * 7 and 56 into 2 * 2 * 2 * 7.
So the area of the mirror would be (2 * 3 * 7)(2 * 3 * 7), and double the area of the mirror is therefore \(2^3 * 3^2 * 7^2\).
For the wall we already have \(2^3 * 7\) for the width. So the length must be \(3^2 * 7\) = 63
Choose .
_________________
Marty Murray | Chief Curriculum and Content Architect
See why Target Test Prep is the top rated GMAT course on GMAT Club. Read Our Reviews
Since the mirror is 42 inches in all sides, it must be a square. Area of a square is A=a^2; 42^2=1764.Area of rectangle is double of that 2 *1764=3528.Now A=lw and we need find w so A/l=w ; 3528/56= 62 Answer!
Bounce1987
Joined: 06 Jul 2014
Last visit: 14 Apr 2026
Posts: 70
Location: India
Concentration: Finance, Entrepreneurship
Schools: Weatherhead '21 Mason '21
GMAT 1: 660 Q48 V32
Products:
2*42*42=56*length
2*42*42= units digit of 8. Answer 63
2*42*42= units digit of 8. Answer 63
Automated notice from GMAT Club BumpBot:
A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.
This post was generated automatically.
_________________
A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.
This post was generated automatically.
_________________
Solving this question helps.
Taking a timed set of similar questions in
GMAT Club Forum Quiz →
is even better.
Moderator:
Announcements
Monday, Sep 14, 2026
11:30am NY / 3:30pm London / 9pm Mumbai
Subscribe to GMAT Club for New Podcast Episodes, Debriefs, & Insightful Sessions on GMAT Preparation
Tuck at Dartmouth
AI at Dartmouth Tuck: How the School Is Preparing Leaders for the Age of Artificial Intelligence
Inside the courses, research, and hands-on learning defining wise, decisive leadership in an AI-driven world.
Read More
Inside the courses, research, and hands-on learning defining wise, decisive leadership in an AI-driven world.
Read More
Top 5 GMAT Debrief Videos
Success stories and strategies from high-scoring candidates.