21st International Mathematical Olympiad 1979 Problems & Solutions

A1.  Let m and n be positive integers such that:       m/n = 1 - 1/2 + 1/3 - 1/4 + ... - 1/1318 + 1/1319. Prove that m is divisible by 1979. A2.  A prism with pentagons A1A2A3A4A5 and B1B2B3B4B5 as the top and bottom faces is given. Each side of the two pentagons and each of the 25 segments AiBj is colored red or green. Every triangle whose vertices are vertices of the prism