Each of A, B, C and D is a positive integer with the proviso that A ≤ B ≤ C ≤ D ≤ 20.

Determine the total number of quadruplets (A, B, C, D) such that A*B*C*D is divisible by 50.

20 20 20 20     thats 1

x   20 20 20    19 possible sol.

x   y  20 20     19^2  sol

x y z 20        please continue  with one twenty :and then  0 twenties

 

I MUST QUIT NOW

9

Posted by Ady TZIDON on 2010-08-20 14:38:49