GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 22 Nov 2019, 11:47 ### 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

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

Track

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.  # What could be the range of a set consisting of odd multiples

Author Message
TAGS:

### Hide Tags

Senior Manager  B
Affiliations: SPG
Joined: 15 Nov 2006
Posts: 270
What could be the range of a set consisting of odd multiples  [#permalink]

### Show Tags

2
25 00:00

Difficulty:   15% (low)

Question Stats: 76% (01:22) correct 24% (01:23) wrong based on 468 sessions

### HideShow timer Statistics

What could be the range of a set consisting of odd multiples of 7?

A. 21
B. 24
C. 35
D. 62
E. 70

Originally posted by dimitri92 on 27 May 2010, 01:48.
Last edited by Bunuel on 09 Jul 2013, 06:56, edited 1 time in total.
Renamed the topic, edited the question and added the OA.
Math Expert V
Joined: 02 Sep 2009
Posts: 59266
Re: odd multiples of 7?  [#permalink]

### Show Tags

26
8
amitjash wrote:
I am sorry... I may sound a bit stupid but still i dont understand. First of all i dont understand what does it mean by range and why range must be even multiple of 7?

What could be the range of a set consisting of odd multiples of 7?
A. 21
B. 24
C. 35
D. 62
E. 70

The range of a set is the difference between the largest and smallest elements of a set.

Set consists of odd multiples of 7 (numbers of a type $$7*odd$$), so there can be following elements: ..., -7, 7, 21, 35, ...

The range of this set would be: $$7*odd_{max}-7*odd_{min}=7(odd_{max}-odd_{min})=7*even$$, (as odd-odd=even). So the range is even multiple of 7.

Hope it's clear.
_________________
Manager  Joined: 30 Jun 2004
Posts: 126
Location: Singapore
Re: odd multiples of 7?  [#permalink]

### Show Tags

9
E.

A set of odd multiples of 7 would be something like 7, 21, 35, 49....

The range would always be an even number multiple of 7.
##### General Discussion
Director  Joined: 03 May 2007
Posts: 621
Schools: University of Chicago, Wharton School
Re: odd multiples of 7?  [#permalink]

### Show Tags

dimitri92 wrote:
What could be the range of a set consisting of odd multiples of 7?
a)21
b)24
c)35
d)62
e)70

I like the question.

The range of the set of multiples of 7 must be even multiple of 7. Which is only 70 among the answer choices.
Manager  Joined: 17 Mar 2010
Posts: 128
Re: odd multiples of 7?  [#permalink]

### Show Tags

I am sorry... I may sound a bit stupid but still i dont understand. First of all i dont understand what does it mean by range and why range must be even multiple of 7?
Intern  Joined: 16 Feb 2006
Posts: 28
Location: ZURICH
Re: odd multiples of 7?  [#permalink]

### Show Tags

5
1
As I know range means : Largest no. - Smallest no. in a set.
And as per the question its asking what could be the range .

Odd multiples of 7 means 7 *(2k+1) ..so smallest in this set can me where k=0 i.e 7
and largest in this set can be 7*(2k+1) where k is some finite max number.
So Range = 7*(2k+1) - 7 = 14k . This range should be in the form of a multiple of 14 , and as per the options I can see only 70 is the multiple of 14 .

_________________
TRY N TRY UNTIL U SUCCEED
Manager  Joined: 17 Mar 2010
Posts: 128
Re: odd multiples of 7?  [#permalink]

### Show Tags

Thank you guys.... I really appreciate the job you are doing on this forum.. Keep it up...
Thanks Again for your great help...
Intern  Joined: 19 Jun 2010
Posts: 18
Re: odd multiples of 7?  [#permalink]

### Show Tags

1
range= last number( which is odd number) -first number( which is odd number too)
in this case, range = odd number - odd number = even number.
this narrow the answer to b,d, e
from property of factor: a multiple of 7 - multiple of 7= multiple of 7
so 70 is the only multiple of 7 among b,d and e
Director  Joined: 23 Apr 2010
Posts: 504
Re: odd multiples of 7?  [#permalink]

### Show Tags

Here you go:

Range = the difference between the greatest and the smallest numbers in the sequence. Our sequence is odd and is a multiple of 7. Every number in that sequence can be represented like this: 7*(2n+1) where n is any positive integer.

Range = 7*(2m + 1) - 7*(2n + 1) = 7*2*(m-n) = 14 * (m-n).

m, n - any positive integers

The answer must be divisible by 14, which is only 70.

Manager  Joined: 16 Apr 2008
Posts: 59
Re: odd multiples of 7?  [#permalink]

### Show Tags

[quote="Fistail] I like the question.

The range of the set of multiples of 7 must be even multiple of 7. Which is only 70 among the answer choices.[/quote]

I was banging my head against the wall after reading the question. Thanks Fistail, never occured to me that it can be so easy to answer.
Intern  Joined: 21 Jun 2010
Posts: 5
Re: odd multiples of 7?  [#permalink]

### Show Tags

you have taken 2n+1 as it says to find the odd no. range.....what if he says to find the even no. range then how should we move........
SVP  Joined: 06 Sep 2013
Posts: 1552
Concentration: Finance
Re: What could be the range of a set consisting of odd multiples  [#permalink]

### Show Tags

dimitri92 wrote:
What could be the range of a set consisting of odd multiples of 7?

A. 21
B. 24
C. 35
D. 62
E. 70

Well it has to be a multiple of 7 and since Odd - Odd = Even, then only E fits the bill

Hope it helps
Cheers!
J Intern  Joined: 09 Aug 2014
Posts: 19
Re: What could be the range of a set consisting of odd multiples  [#permalink]

### Show Tags

Bunuel wrote:
amitjash wrote:
I am sorry... I may sound a bit stupid but still i dont understand. First of all i dont understand what does it mean by range and why range must be even multiple of 7?

What could be the range of a set consisting of odd multiples of 7?
A. 21
B. 24
C. 35
D. 62
E. 70

The range of a set is the difference between the largest and smallest elements of a set.

Set consists of odd multiples of 7 (numbers of a type $$7*odd$$), so there can be following elements: ..., -7, 7, 21, 35, ...

The range of this set would be: $$7*odd_{max}-7*odd_{min}=7(odd_{max}-odd_{min})=7*even$$, (as odd-odd=even). So the range is even multiple of 7.

Hope it's clear.

Thank you!
I really like your post Current Student D
Joined: 12 Aug 2015
Posts: 2549
Schools: Boston U '20 (M)
GRE 1: Q169 V154 Re: What could be the range of a set consisting of odd multiples  [#permalink]

### Show Tags

Here is my solution to this one-->

Range must be even and a multiple of 7.

Hence Range must be a multiple of 14.

Only Choice E is a multiple of 14

Hence E

_________________
Target Test Prep Representative V
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8463
Location: United States (CA)
Re: What could be the range of a set consisting of odd multiples  [#permalink]

### Show Tags

dimitri92 wrote:
What could be the range of a set consisting of odd multiples of 7?

A. 21
B. 24
C. 35
D. 62
E. 70

Since the range of a set of numbers is defined as the difference between the largest number and the smallest number in the set, we can just calculate the difference between odd multiples of 7. For example, the difference between 21 and 7 is 14, between 35 and 7 is 28, between 77 and 21 is 56.

From the above examples, we see that the difference between two odd multiples of 7 must be an even multiple of 7 or, equivalently, a multiple of 14. Therefore, the correct answer is 70 since it is the only number in the answer choices that is a multiple of 14.

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button. Re: What could be the range of a set consisting of odd multiples   [#permalink] 15 Oct 2019, 20:00
Display posts from previous: Sort by

# What could be the range of a set consisting of odd multiples  