Two numbers are randomly selected without replacement from the first 20 positive integers. Find the probability that the sum of these two numbers is 17.
20 c 2 = 190 ways to select 2 numbers
1 16
2 15
3 14
4 13
5 12
6 11
7 10
8 9 8 ways to add to 17 8 out of 190 = 8 /190 = 4/95
