All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars
 perplexus dot info

 Counting Quadruplets III (Posted on 2011-02-06)
Determine the total number of quadruplets (A,B, C, D) of positive integers with A ≤ B ≤ C ≤ D ≤ 25, such that (A+B)*(C+D) is divisible by |A*D – B*C|, whenever A*D ≠ B*C.

Note: |x| refers to the absolute value of x.

 No Solution Yet Submitted by K Sengupta No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
 re: computer solution ... Do me a favor , Charlie | Comment 2 of 6 |
(In reply to computer solution by Charlie)

Do me a favor ,  Charlie

I'®ve tried to evaluate manually  the total number of quadruplets (A,B, C, D) of positive integers with A <= B <= C <= D <= 25, and got 20175.

Tot= C(25,4)+25*C(24,2)+2*C(25,2)+25=20175

Please, check my result by adding another counter to your program and make me happy (or busy again).

Thank you.

Edited on February 7, 2011, 1:59 am
 Posted by Ady TZIDON on 2011-02-07 01:51:06

 Search: Search body:
Forums (0)
Random Problem
Site Statistics
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox: