Suppose for any positive integer n, s(n) is the remainder when n is divided by 19. Find the number of pairs of integers (a,b), such that 1≤a≤b≤18, and for all k=1,2,...,18
k+s(ka)+s(kb)≥20

Question

Suppose for any positive integer n, s(n) is the remainder when n is divided by 19. Find the number of pairs of integers (a,b), such that 1≤a≤b≤18, and for all k=1,2,...,18
k+s(ka)+s(kb)≥20

anonymous · Answer

If someone here can help you with that, I will be truly impressed. Good luck! Looks like this same question was posed a month ago: http://openstudy.com/study#/updates/51ba0cede4b0012787faa168

loser66 · Answer

@terenzreignz