• Get 300+ Practice Questions

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 • 1 Hour Free BEAT THE GMAT EXCLUSIVE 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 • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE 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

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

## Set K consists of a finite number of consecutive

tagged by: Vincen

This topic has 1 expert reply and 0 member replies

### Top Member

Vincen Legendary Member
Joined
07 Sep 2017
Posted:
777 messages
Followed by:
3 members
6

#### Set K consists of a finite number of consecutive

Thu Feb 08, 2018 8:09 am
Set K consists of a finite number of consecutive odd integers. If x is the smallest number in K and y is the greatest, then y - x =

(1) The average (arithmetic mean) of set K is -36.

(2) There are 8 numbers in set K.

The OA is the option B.

I don't know how can I use the statement (2) to get the value of y-x. Can any expert give me some help here? Please.

### GMAT/MBA Expert

Brent@GMATPrepNow GMAT Instructor
Joined
08 Dec 2008
Posted:
11780 messages
Followed by:
1232 members
5254
GMAT Score:
770
Thu Feb 08, 2018 10:15 am
Vincen wrote:
Set K consists of a finite number of consecutive odd integers. If x is the smallest number in K and y is the greatest, then y - x =

(1) The average (arithmetic mean) of set K is -36.

(2) There are 8 numbers in set K.
Target question: What is the value of y - x?

Given: Set K consists of a finite number of consecutive odd integers

Statement 1: The average (arithmetic mean) of set K is -36
There's a nice rule that says, "In a set where the numbers are equally spaced, the mean will equal the median."
For example, in each of the following sets, the mean and median are equal:
{7, 9, 11, 13, 15}
{-1, 4, 9, 14}
{3, 4, 5, 6}

Set K consists of consecutive odd integers, so the values are EQUALLY SPACED.
Since the mean of set K is -36, we know that the MEDIAN is -36 as well.
HOWEVER, we don't know the number of elements in set K.
So, consider these two possible sets that yield conflicting answers to the target question:
Case a: set K = {-37, -35}, so the average is -36. In this case y - x = -35 - (-37) = 2
Case b: set K = {-39, -37, -35, -33}, so the average is -36. In this case y - x = -33 - (-39) = 6
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: There are 8 numbers in set K.
We already know that the numbers are consecutive ODD integers.
This means that each number in the set is 2 GREATER than the one before it.
So, if we let x = the smallest (1st) value in set K
Then x + 2 = the 2nd value in set K
And x + 4 = the 3rd value in set K
And x + 6 = the 4th value in set K
And x + 8 = the 5th value in set K
And x + 10 = the 6th value in set K
And x + 12 = the 7th value in set K
And x + 14 = the 8th value in set K
In other words, x + 14 = y, the largest value in set K

So, y - x = (x + 14) - x = 14
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Cheers,
Brent

_________________
Brent Hanneson – Creator of GMATPrepNow.com
Use our video course along with

Check out the online reviews of our course
Come see all of our free resources

GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!

### Top First Responders*

1 GMATGuruNY 93 first replies
2 Brent@GMATPrepNow 39 first replies
3 Jay@ManhattanReview 34 first replies
4 Rich.C@EMPOWERgma... 28 first replies
5 Scott@TargetTestPrep 11 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

### Most Active Experts

1 GMATGuruNY

The Princeton Review Teacher

138 posts
2 Brent@GMATPrepNow

GMAT Prep Now Teacher

134 posts
3 Scott@TargetTestPrep

Target Test Prep

115 posts
4 Jeff@TargetTestPrep

Target Test Prep

104 posts
5 Max@Math Revolution

Math Revolution

92 posts
See More Top Beat The GMAT Experts