Hi Tutor can you help me to solve this

Considering the following set to create your password: A,B,C,D,E,F,1,2,3,4,5,6 determine the following: a. How many six-character passwords that contain at least one letter and at least one digit and no character are reused? |l b. How many six-character passwords can you make if it contains the same number of letters and digits [in any order) with repeats allowed? | |