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.

(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