|
|
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.
18 Jul 2019, 23:57
Kudos
Bookmarks
A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
85%
(hard)
Question Stats:
38% (02:14) correct
62%
(02:46)
wrong
based on 37
sessions
History
Date
Time
Result
Not Attempted Yet
Is ABC an equilateral triangle?
(1) BD/AD = DC/DB
(2) AB^2 + CD^2 = AD^2 + BC^2
Attachment:
2019-07-19_1054.png [ 12.11 KiB | Viewed 2321 times ]
Pure algebraic questions like this one are no longer part of the GMAT Data Sufficiency syllabus.
For relevant Data Sufficiency questions, please check the Data Sufficiency forum:
Data Sufficiency Forum
Data Sufficiency Forum
saukrit
Joined: 05 Jul 2018
Last visit: 23 Apr 2026
Posts: 378
Given Kudos: 326
Status:Current student at IIMB
Affiliations: IIM Bangalore
Location: India
Concentration: General Management, Technology
Schools: IIMB EPGP'22 (A)
GMAT 1: 600 Q47 V26
GRE 1: Q162 V149
GPA: 3.6
WE:Information Technology (Consulting)
Products:
21 Jul 2019, 00:07
Kudos
Bookmarks
Bunuel
In the figure above
As per statement 1
\(\frac{BD}{AD}= \frac{DC}{DB}\)
Also Angle BDA= Angle CDB
Hence, Triangle BDA is similar to triangle CDB (ratio of 2 sides and the adjoining angle are equal)
Now Angle CBD= Angle DAB
Also, Angle ABD= Angle BCD
Adding the above 2 equation We get that
Angle CBD + Angle ABD = Angle DAB+ Angle BCD
Therefore In Triangle ABC, One angle is the sum of the other 2 angles
Hence, it can not be an equilateral triangle.
So Statement 1 alone is SUFFICIENT to surely answer a NO
As per statement 2 however,
\(AB^2 + CD^2 = AD^2 + BC^2\)
Rearranging above equation we have
\(AB^2-AD^2=BC^2-CD^2\)
\(BD^2 =BD^2\)
This gives us no information to decide whether Triangle ABC is equilateral or not
Hence, Statement 2 is not sufficient to answer the question.
Hence, IMO, A is the answer.
Moderator:
