a) You are supposed to create a new password. Min 6 characters and max 8 characters. Alphanumeric characters (letters & numbers). Case insensitive. The password has to contain at least one digit. How many possible passwords are there?

b) If passwords may contain lower case letters and digits, how many 6-character passwords start with a lower case letter ‘a’ or ends with a lower case letter ‘z’?

Question

a) You are supposed to create a new password. Min 6 characters and max 8 characters. Alphanumeric characters (letters & numbers). Case insensitive. The password has to contain at least one digit. How many possible passwords are there?

b) If passwords may contain lower case letters and digits, how many 6-character passwords start with a lower case letter ‘a’ or ends with a lower case letter ‘z’?

mathstudent55 · Answer

Find the number of possibilities for 6, 7, and 8 characters separately and then add them together.