Summer is Coming! Join the Game of Timers Competition to Win Epic Prizes. Registration is Open. Game starts Mon July 1st.

It is currently 17 Jul 2019, 20:11

Close

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
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.

Close

Request Expert Reply

Confirm Cancel

If m equals the sum of the even integers from 2 to 16

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Senior Manager
Senior Manager
avatar
Status: Finally Done. Admitted in Kellogg for 2015 intake
Joined: 25 Jun 2011
Posts: 463
Location: United Kingdom
Concentration: International Business, Strategy
GMAT 1: 730 Q49 V45
GPA: 2.9
WE: Information Technology (Consulting)
If m equals the sum of the even integers from 2 to 16  [#permalink]

Show Tags

New post 01 Mar 2012, 15:07
1
5
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

78% (01:30) correct 22% (01:18) wrong based on 206 sessions

HideShow timer Statistics


If m equals the sum of the even integers from 2 to 16, inclusive, and n equals the sum of the odd integers from 1 to 15, inclusive, what is the value of m - n ?

(A) 1
(B) 7
(C) 8
(D) 15
(E) 16

Any idea how can the answer be
C?

_________________
Best Regards,
E.

MGMAT 1 --> 530
MGMAT 2--> 640
MGMAT 3 ---> 610
GMAT ==> 730
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 56277
Re: If m equals the sum of the even integers from 2 to 16  [#permalink]

Show Tags

New post 01 Mar 2012, 15:27
1
3
enigma123 wrote:
If m equals the sum of the even integers from 2 to 16, inclusive, and n equals the sum of the odd integers from 1 to 15, inclusive, what is the value of m - n ?
(A) 1
(B) 7
(C) 8
(D) 15
(E) 16

Any idea how can the answer be ?


Even integer from 2 to 16, inclusive (2, 4, 6, ..., 16) as well as odd integers from 1 to 15, inclusive (1, 3, 5, ..., 15) represent evenly spaced set (aka arithmetic progression). Now, the sum of the elements in any evenly spaced set is the mean (average) multiplied by the number of terms, where the mean of the set is (first+last)/2. (Check Number Theory chapter of Math Book for more: math-number-theory-88376.html)

There are 8 even integers from 2 to 16, inclusive, their sum equals to (first+last)/2*(number of terms)=(2+16)/2*8=72;

There are 8 odd integers from 1 to 15, inclusive, their sum equals to (first+last)/2*(number of terms)=(1+15)/2*8=64;

Difference: 72-64=8,

Answer: C.

Or: 2+4+6+8+10+12+14+16-(1+3+5+7+9+11+13+15)= (2-1)+(4-3)+(6-5)+(8-7)+(10-9)+(12-11)+(14-13)+(16-15)=1+1+1+1+1+1+1+1=8.

Answer: C.
_________________
SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1787
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: If m equals the sum of the even integers from 2 to 16  [#permalink]

Show Tags

New post 27 Oct 2014, 21:58
enigma123 wrote:
If m equals the sum of the even integers from 2 to 16, inclusive, and n equals the sum of the odd integers from 1 to 15, inclusive, what is the value of m - n ?

(A) 1
(B) 7
(C) 8
(D) 15
(E) 16

Any idea how can the answer be
C?


2 * 1 = 2

2 * 8 = 16

There are 8 even integers from 2 to 16

For every even integer, there is a 1 less odd integer whose subtraction will give result 1

(16-15) + (14-13) ................. (2 - 1)

This is repeated 8 times = 8 * 1 = 8

Answer = C
_________________
Kindly press "+1 Kudos" to appreciate :)
Intern
Intern
avatar
B
Joined: 28 Nov 2017
Posts: 2
Re: If m equals the sum of the even integers from 2 to 16  [#permalink]

Show Tags

New post 24 Feb 2018, 03:04
Sum of 1st n odd integers is n^2 & Sum of 1st n even integers is n^2+n

-> (sum of n even integers) - (sum of n odd integers) = (n^2+n) - (n^2) = n

Here, There are 8 even integers between 2 and 16 (inclusive) and 8 odd integers between 1 and 15 (inclusive).

-> n= 8

Ans:C
GMAT Club Bot
Re: If m equals the sum of the even integers from 2 to 16   [#permalink] 24 Feb 2018, 03:04
Display posts from previous: Sort by

If m equals the sum of the even integers from 2 to 16

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne