perplexus.info :: Just Math : Sum (expression) = 10*n

Sum (expression) = 10*n (Posted on 2011-02-22)

Determine all possible positive integer values of n that satisfy this equation:

_j=n

^j=1

(x+j-1) (x+j) = 10*n

whenever x is an integer.

Note: For a desired value of n, the above equation holds true for at least one value of x.

Submitted by K Sengupta

Rating: 3.0000 (2 votes)

Solution: (Hide)

The only possible values for n are 4, 7 and 11.

For a detailed explanation, refer to the solution submitted by Daniel in this location.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
re(3): Possible solution	Daniel	2011-02-23 11:41:08
re(2): Possible solution	broll	2011-02-23 07:44:24
re: Possible solution	brianjn	2011-02-23 07:31:29
Possible solution	broll	2011-02-23 07:08:40
So long	brianjn	2011-02-22 20:27:02

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