5. A prime number is a number that is evenly disible by and itself. The prime numbers less than 100 are: 2 3 4 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 Choose a number at random. a) Find the probability that the number is even. b) Find the probability that the sum of the number's digits is even c) Find the probability that the number is greater than 50.