Consider a license plate format with two letters (A-Z) followed by 4 digits (0-9).

a. How many possible sequences are there (examples: JA9926, RR1234)?

b. How many such sequences from part (a) begin withAand end in9(exampleAM2249)?

c. How many such sequences either begin with anXor end in an8, or both (examples:XL4350, XH5188, AZ1528)?

d. How many sequences of 6 symbols are there with two letters and 4 digits if they can occur in any order (examples: 2L93A,33B6R)?