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

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Is the range of numbers {a, b, c, d, e} greater than 10 [#permalink]

Show Tags

11 Oct 2010, 13:50

1

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

(N/A)

Question Stats:

50% (01:26) correct
50% (00:37) wrong based on 10 sessions

HideShow timer Statistics

So, I was preparing a list of important properties to include in the flashcards I was making for the competition and when I was looking for illustrative examples, I came across this one question. I believe this is a good question to test your knowledge of sets and ranges and to really think smartly.

I will post the answer tomorrow, so you guys will have a day to try the question!

Quote:

Is the range of numbers {a, b, c, d, e} greater than 10.

Statement 1: b - d > 10 Statement 2: b is the greatest number in the set.

Re: Sets and Ranges - Challenge Question [#permalink]

Show Tags

12 Oct 2010, 01:00

Range=The distance between two extreme points on the number line -----X---p---q---r--Y----- range= distance between X and Y

Stmnt1: b-d > 10 ===> the distance between b and d on the number line is > 10 hence the range must surely be > 10 even if the rest (a,c and e are kept between b and d) --- SUFF.

stmnt2: b is the grtst # among them; as per the definition of range, two points (extreme points) are required to calculate the range ===> NOT SUFF.

There are many ways to define the range of a set. Most people learn that:

range = largest - smallest

which is a perfectly good way to understand the range for most questions. That definition is equivalent to the following:

range = largest distance between any two elements in a set

So if you know b and d are in your set, and you know that b-d > 10, then the largest distance between any two elements in the set clearly must be greater than 10, and the range is thus greater than 10.
_________________

GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

Re: Sets and Ranges - Challenge Question [#permalink]

Show Tags

14 Oct 2010, 07:22

Easy A.

whiplash2411 wrote:

Is the range of numbers {a, b, c, d, e} greater than 10.

Statement 1: b - d > 10 Statement 2: b is the greatest number in the set.

(1) b - d > 10. So the range must be, at the very least, 10. If b and d are the absolute extremes of the set (so a, c, and e all fall between them), then b - d is the range. If any of a, c, or e are larger or smaller than b or d, then the range will be bigger than b - d. The other three numbers are irrelevant because they can't shrink the range.

Quick examples, let b = 21 and d = 9, so b - d = 11:

{9, 10, 11, 12, 21} - range = 11 {5, 9, 10, 11, 21} - range = 16 {5, 9, 10, 21, 25} - range = 20

Sufficient.

(2) Clearly insufficient, as we have no information about the other numbers.

gmatclubot

Re: Sets and Ranges - Challenge Question
[#permalink]
14 Oct 2010, 07:22

Happy New Year everyone! Before I get started on this post, and well, restarted on this blog in general, I wanted to mention something. For the past several months...

It’s quickly approaching two years since I last wrote anything on this blog. A lot has happened since then. When I last posted, I had just gotten back from...

Post-MBA I became very intrigued by how senior leaders navigated their career progression. It was also at this time that I realized I learned nothing about this during my...