Illinois license plates used to consist of either three letters followed by three digits or two letters followed by four digits. Assume that all the different possible license plates are equally likely.
(a) What is the probability that a randomly chosen plate contains the number 9999? (Round your answer to six decimal places.)
(b) What is the probability that a randomly chosen plate contains the substring WE? (For example, WE4321 or PWE786 are two ways WE might appear. Round your answer to six decimal places.)