Question 917032: He chose a random positive integer factor of 10^99, what's probability that it is also a positive integer multiple of 10^88? Answer by richard1234(7193) (Show Source):
For the factor to be a multiple of 10^88, we must have and . We have 12 choices (88, 89, ..., 99) for a and 12 choices for b, so 144 choices total. There are 100^2 factors of 10^99, so the probability is 144/10000.