+6251 this is just a counting problem, nothing particularly clever about it.
you can do this one.
(10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24, 25, 26, 28, 30, 31, 32, 33, 35, 36, 39, 40, 41, 42, 44, 45, 48, 50, 51, 52, 55, 60, 61, 62, 63, 64, 65, 66, 70, 71, 72, 75, 77, 80, 81, 82, 84, 85, 88, 90, 91, 92, 93, 95, 96, 99) = 59 Numbers
There are: 99 - 10 + 1 = 90 2-digit numbers.
The probability = 59 / 90
Answer: 59/90
