Suppose we want to pick two numbers from {1,2,⋯,100} randomly. What is the probability that the sum of the two picked numbers is divisible by 4?
+515 HINT:
well, there are 25 multiples of 4.
4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, 72, 76, 80, 84, 88, 92, 96, 100
