Suppose that license plates can be two, three, four, or five letters long, taken from the alphabets A to Z. All letters are possible, including repeats. A license plate is chosen at random in such a way so that all plates are equally likely.
(a) What is the probability that the plate is “A-R-R?”
(b) What is the probability that the plate is four letters long?
(c) What is the probability that the plate is a palindrome?
(d) What is the probability that the plate has at least one “R?”