• NEW! FREE Beat The GMAT Quizzes
Hundreds of Questions Highly Detailed Reporting Expert Explanations
• 7 CATs FREE!
If you earn 100 Forum Points

Engage in the Beat The GMAT forums to earn
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 How many rectangles are found in the lattice below? This topic has 2 expert replies and 0 member replies GMAT/MBA Expert How many rectangles are found in the lattice below? Timer 00:00 Your Answer A B C D E Global Stats Difficult [GMAT math practice question] How many rectangles are found in the lattice below? A. 90 B. 100 C. 120 D. 150 E. 180 _________________ 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
Free Resources-30 day online access & Diagnostic Test
Email to : info@mathrevolution.com

GMAT/MBA Expert

GMAT Instructor
Joined
25 May 2010
Posted:
15344 messages
Followed by:
1864 members
13060
GMAT Score:
790
Max@Math Revolution wrote:
[GMAT math practice question]

How many rectangles are found in the lattice below?

A. 90
B. 100
C. 120
D. 150
E. 180

To form a rectangle, we must combine as HORIZONTAL LENGTH with a VERTICAL LENGTH:

Horizontal length:
Number of ways to choose a horizontal length of 1:
AB, BC, CD, DE, EF = 5
Number of ways to choose a horizontal length of 2:
AC, BD, CE, DF = 4
Number of ways to choose a horizontal length of 3:
AC, BE, CF = 3
Number of ways to choose a horizontal length of 4:
Number of ways to choose a horizontal length of 5:
AF = 1
Total ways = 5+4+3+2+1 = 15

Vertical length:
Number of ways to choose a vertical length of 1:
AG, GH, HI, IJ = 4
Number of ways to choose a vertical length of 2:
AH, GI, HJ = 3
Number of ways to choose a vertical length of 3:
AI, GJ = 2
Number of ways to choose a vertical length of 4:
AJ = 1
Total ways = 4+3+2+1 = 10

To combine our horizontal options with our vertical options, we multiply:
15*10 = 150

_________________
Mitch Hunt
Private Tutor for the GMAT and GRE
GMATGuruNY@gmail.com

If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon.

Available for tutoring in NYC and long-distance.
Student Review #1
Student Review #2
Student Review #3

Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.

GMAT/MBA Expert

Legendary Member
Joined
24 Jul 2015
Posted:
2389 messages
Followed by:
32 members
19
GMAT Score:
=>

Each rectangle is uniquely determined by the intersections between two vertical lines and two horizontal lines.
Since we have 6 vertical lines and 5 horizontal lines, the number of rectangles is 6C2*5C2 = 15*10 = 150.

_________________

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 Free Resources-30 day online access & Diagnostic Test Unlimited Access to over 120 free video lessons-try it yourself Email to : info@mathrevolution.com • 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 • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Award-winning private GMAT tutoring Register now and save up to$200

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

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

Top First Responders*

1 Ian Stewart 57 first replies
2 Brent@GMATPrepNow 31 first replies
3 Jay@ManhattanReview 29 first replies
4 GMATGuruNY 20 first replies
5 ceilidh.erickson 15 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

Most Active Experts

1 Scott@TargetTestPrep

Target Test Prep

211 posts
2 Max@Math Revolution

Math Revolution

88 posts
3 Brent@GMATPrepNow

GMAT Prep Now Teacher

70 posts
4 Ian Stewart

GMATiX Teacher

65 posts
5 GMATGuruNY

The Princeton Review Teacher

39 posts
See More Top Beat The GMAT Experts