101st Group

101st Group
Group the consecutive counting numbers as follows: (1), (2, 3), (4, 5, 6), (7, 8, 9, 10), . . Notice that there is one number in the first group, two numbers in the second group, three in the third, etc. What is the sum of the numbers in the 101st group?
Source: mathcontest.olemiss.edu 10/17/2011

SOLUTION
This problem is similar to problem “199 Numbers” dated 3/12/2007 and to problem “Consecutive Counting Groups” dated 1/18/2010. Please see them for solution.

Answer: 515201.

Advertisements

About mvtrinh

Retired high school math teacher.
This entry was posted in Problem solving and tagged , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s