Last visit was: 29 Apr 2026, 16:22 It is currently 29 Apr 2026, 16:22
Home
Messages
Tests
Schools
Events
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
   1   2 
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 29 Apr 2026
Posts: 109,975
Own Kudos:
811,984
 [1]
Given Kudos: 105,949
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,975
Kudos: 811,984
 [1]
The sum of the even numbers between 1 and n is 79*80, where 30 Dec 2025, 09:42
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
eaat
Hi, can someone explain why it's not A = 79?

Using the sum of even numbers formula Sum = n(n+1); we know that n = 79. Why can't we stop here and let n = 79?
Show more
You are confusing two different n’s.

In the formula n(n + 1), n means how many even numbers are being added. In the question, n means the upper limit of the range. Those are not the same thing.

Please study the solutions provided for more.
   1   2 
Moderators:
Bunuel
Math Expert
109975 posts
Krunaal
Tuck School Moderator
852 posts