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

Redeem

Weighted averages - To find the average income of the town

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 641
Joined: Tue Feb 14, 2012 3:52 pm
Thanked: 11 times
Followed by:8 members

Weighted averages - To find the average income of the town

by gmattesttaker2 » Sun Feb 09, 2014 12:03 am
Hello,

Can you please assist with this question? I was not sure how to solve Statement 2.

What is the average income at Town A?
(1) The combined income of the people at Town A is $42,000,000.

(2) 60 percent of the people at Town A have an average income of
$36,000 and the rest have an average income of $55,000.

OA: B


Thanks,
Sri
Top
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 » Sun Feb 09, 2014 4:44 am
gmattesttaker2 wrote: What is the average income in Town A?

(1) The combined income of the people in Town A is $42,000,000.

(2) 60 percent of the people in Town A have an average income of
$36,000 and the rest have an average income of $55,000.
Statement 1: The combined income of the people in Town A is $42,000,000.
Without knowing the number of people in Town A, we cannot determine the average income.
INSUFFICIENT.

Statement 2: 60 percent of the people in Town A have an average income of $36,000 and the rest have an average income of $55,000.
60% = 3/5.
Thus, of every 5 people, 3 earn an average of $36000, while the remaining 2 people earn an average of $55000.
Resulting average for every 5 people = (3*36000 + 2*55000)/5 = 43,600.
SUFFICIENT.

The correct answer is B.
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
Top

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

by [email protected] » Mon Feb 10, 2014 12:15 am
Hi Sri,

Mitch has provided a great explanation for this question. I want to add a bit more "proof" to Fact 2, in the (likely) event that you face something like this on the Official GMAT...

Fact 2 essentially tells you about a 60/40 ratio between people who average $36,000 and those who average $55,000.

That could be
3 @ $36,000
2 @ $55,000

Average = [3(36,000) + 2(55,000)]/5 = 43,600

It could also be
6 @ $36,000
4 @ $55,000

Average = [6(36,000) + 4(55,000)]/10 = 43,600

Since the average stays the same, Fact 2 is SUFFICIENT. If you're ever unsure about how to assess ratio "data", then just track two examples - if the answers are the same, then you're dealing with Sufficient information.

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
Post new topic Post Reply
• Page 1 of 1