BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

What is the average of the terms in set J? (1) The sum of a

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Legendary Member
Posts: 1100
Joined: Sat May 10, 2014 11:34 pm
Location: New Delhi, India
Thanked: 205 times
Followed by:24 members

What is the average of the terms in set J? (1) The sum of a

by GMATinsight » Thu Oct 08, 2015 10:08 am
What is the average of the terms in set J?

(1) The sum of any three terms in set J is 21.
(2) Set J consists of 12 total terms.

Answer: option A
"GMATinsight"Bhoopendra Singh & Sushma Jha
Most Comprehensive and Affordable Video Course 2000+ CONCEPT Videos and Video Solutions
Whatsapp/Mobile: +91-9999687183 l [email protected]
Contact for One-on-One FREE ONLINE DEMO Class Call/e-mail
Most Efficient and affordable One-On-One Private tutoring fee - US$40-50 per hour
Top
Source: — Data Sufficiency |
User avatar
Legendary Member
Posts: 1100
Joined: Sat May 10, 2014 11:34 pm
Location: New Delhi, India
Thanked: 205 times
Followed by:24 members

by GMATinsight » Thu Oct 08, 2015 10:09 am
GMATinsight wrote:What is the average of the terms in set J?

(1) The sum of any three terms in set J is 21.
(2) Set J consists of 12 total terms.

Answer: option A
Question : What is the average of the terms in set J?

Statement 1: The sum of any three terms in set J is 21.
this is possible only when all the terms in the set are 7 or when there are only three terms with sum of them as 21
in both cases the average of terms will be 7. hence
SUFFICIENT

Statement 2: Set J consists of 12 total terms
There is no information about sum of the terms. Hence,
NOT SUFFICIENT

Answer: option A
"GMATinsight"Bhoopendra Singh & Sushma Jha
Most Comprehensive and Affordable Video Course 2000+ CONCEPT Videos and Video Solutions
Whatsapp/Mobile: +91-9999687183 l [email protected]
Contact for One-on-One FREE ONLINE DEMO Class Call/e-mail
Most Efficient and affordable One-On-One Private tutoring fee - US$40-50 per hour
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Thu Oct 08, 2015 11:11 am
GMATinsight wrote:What is the average of the terms in set J?

(1) The sum of any three terms in set J is 21.
(2) Set J consists of 12 total terms.
Target question: What is the average of the terms in set J?

Statement 1: The sum of any three terms in set J is 21.
This is a very powerful statement, because it tells us that all of the numbers in the set are equal.
Let's let a,b and c be three of the numbers in set J.
We know that a + b + c = 21
Notice that if I replace ANY of these three values (a,b or c) with d, the sum must still be 21.
This tells us that a, b and c must all equal d.
Using similar logic, I can show that ALL of the numbers in the set must equal d, which means all of the numbers in the set must be equal.
If all of the numbers are equal, then EVERY number must equal 7, which means the average of set J MUST equal 7
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: Set J consists of 12 total terms
There are several possible scenarios that satisfy this statement. Here are two.
Case a: J = {2,2,2,2,2,2,2,2,2,2,2,2}, in which case the average of set J = 2
Case b: J = {1,1,1,1,1,1,1,1,1,1,1,1}, in which case the average of set J = 1
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer = A

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Post new topic Post Reply
• Page 1 of 1