PLEASE TYPE ONLY*** Exercise 5.3.3: Counting license plate numbers. License plate numbers in a certain state consists of seven characters. The first character is a digit (0 through 9). The next four...

PLEASE TYPE ONLY***

Exercise 5.3.3: Counting license plate numbers.

License plate numbers in a certain state consists of seven characters. The first character is a digit (0 through 9). The next four characters are capital letters (A through Z) and the last two characters are digits. Therefore, a license plate number in this state can be any string of the form:

Digit-Letter-Letter-Letter-Letter-Digit-Digit

(b)

How many license plate numbers are possible if no digit appears more than once?

(c)

How many license plate numbers are possible if no digit or letter appears more than once