Five thousand raffle tickets are sold. One first prize of $1000, two second prizes of $500 each, and three third prizes of $100 each will be awarded, with all winners selected randomly.

a. If you purchased one ticket, what are your expected gross winnings?

b. If you purchased ten tickets, what are your expected gross winnings?

c. If the tickets were sold for $1 each, how much profit goes to the raffle sponsor?