• 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