Problem: A bank gives each new customer a 4-digit code number which allows the new customer to create their own...

Problem: A bank gives each new customer a 4-digit code number which allows the new customer to create their own password. The code number is assigned randomly from the digits 1, 3, 5, and 7, and no digit is repeated. 8. What is the probability that the code number for a new customer will begin or end with a 7? Do I multiply 7, 5, 3, and 1 to get 150 and put 2 over it or is it another way? Brwon, this page is about permutations.