Question

how many 6 - slots codes can be made up using 2 letters followed by 2 digits followed by 2 letters where All of the following conditions must be met:
a. the allowable letters are A through G
b. the allowable digits are 2 through 7
c. no digit can be repeated

Answer 1

So we have 7 letters, and 6 digits

number of codes = 7x6 x 6x5 x 5x4
= 42(30)(20) = 25200