If the sum of k consecutive integers is represented by k(k+1 : PS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 19 Jan 2017, 23:26

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If the sum of k consecutive integers is represented by k(k+1

Author Message
Intern
Joined: 09 Aug 2004
Posts: 13
Followers: 0

Kudos [?]: 5 [0], given: 0

If the sum of k consecutive integers is represented by k(k+1 [#permalink]

### Show Tags

26 May 2005, 11:39
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If the sum of k consecutive integers is represented by k(k+1)/2 what is the sum of integers between n and m where 0<n<m
Director
Joined: 18 Apr 2005
Posts: 548
Location: Canuckland
Followers: 1

Kudos [?]: 37 [0], given: 0

### Show Tags

26 May 2005, 13:29
say f(k) = k(k+1)/2

then Sum from n to m = f(m) - f(n-1)
Director
Joined: 18 Feb 2005
Posts: 673
Followers: 1

Kudos [?]: 6 [0], given: 0

### Show Tags

26 May 2005, 14:42
first term = m

last term =n

first find the number of terms N (assumption is they are all consequtive)

n+(N-1)*1 = m ==> num of terms = m-n+1

Now find the sum ofthe series between n and m

Sum = N/2{2*first term + (N-1) difference between 2 terms)

= (m-n+1)/2{2*n +(m-n)*1}

==> (m-n+1)(m+n)/2
SVP
Joined: 05 Apr 2005
Posts: 1731
Followers: 5

Kudos [?]: 74 [0], given: 0

### Show Tags

26 May 2005, 18:03
iris wrote:
If the sum of k consecutive integers is represented by k(k+1)/2 what is the sum of integers between n and m where 0<n<m

the question seems incomplete. it should be : If the sum of consecutive integers [b]from 1 to k is represented by k(k+1)/2 what is the sum of integers between n and m where 0<n<m.

if so the sum = (m-n-1)(m+n)/2
Re: PS: Interesting question   [#permalink] 26 May 2005, 18:03
Display posts from previous: Sort by