If triangles ABC and CDE are each equilateral, what is the s

This topic has expert replies
Source: — Data Sufficiency |

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Mon Feb 11, 2019 5:54 pm

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

BTGmoderatorDC wrote:Image


If triangles ABC and CDE are each equilateral, what is the sum of the perimeters of the two triangles?

(1) Line segment AE measures 25 meters.

(2) Side BC is 2/3 as long as side DE.
Statement 1:
Case 1: AC = 10 and CE = 15, with the result that AE = 10+15 = 25
In this case, ABC + CDE = (10+10+10) + (15+15+15) = 75.
Case 2: AC= 5 and CD = 20, with the result that AE = 5+20 = 25
In this case, ABC + CDE = (5+5+5) + (20+20+20) = 75.
Since the sum of the perimeters is the same in each case, SUFFICIENT.

Statement 2:
Case 1: BC = 10 and DE = 15, with the result that BC/DE = 10/15 = 2/3
In this case, ABC + CDE = (10+10+10) + (15+15+15) = 75.
Case 2: BC = 2 and DE = 3, with the result that BC/DE = 2/3
In this case, ABC + CDE = (2+2+2) + (3+3+3) = 15.
Since the sum of the perimeters is NOT the same in each case, INSUFFICIENT.

The correct answer is A.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3