Mr. B has built a new home and he has applied for telephone service. A 5 digit phone number was assigned to him. What is the probability that his number will not contain any repeated digits (from 0 to 9)?
Assuming that we could have a number with all 0's, there are 100,000 numbers possible [10 digits possible in each of the 5 places = 10^5 = 100,000 ]
We want to choose the sets of any 5 of the 10 numbers permuted = P(10,5) = 30,240
P = 30,240 / 100,000 = 30.24%
+77 
