A local bookstore intended to award three gift certificates in the amounts $100, $50, and $25 to the first, second, and third customer to identify a mystery author. Unfortunately, a careless clerk in charge of mailing forgot the order and just randomly placed the gift certificates in the already addressed envelopes.
(a) List the sample space using F, S, and T for the three persons.
(b) State the compositions of the events
A = [exactly one certificate is sent to the correct person]
B = [all of the certificates are sent to incorrect persons]