to use telephone banking to pay bills, the coutomer has to eneter the last three digits of each bill. the numbers 0 to 9 can be used.
a. What is the probability that a person has two bill to register with the same last three digits?
The first bill can be any three digits so what you are concerned with is the probability that any of the other bills will be a specific 3 digit number.Originally Posted by kelsey
there are 10 possible digits for each of the 3 places so the probability is $\displaystyle \frac {1}{10*10*10}$ or $\displaystyle \frac {1}{1000}$