Hello, I would like some help in solving these problems. Please explain how you arrived at your answer if you don't mind.

1. Ten finalists are competing in a race at the Canada games:
a) In how many different orders can the competitors finish the race?
b) How many ways could the gold, silver, and bronze medal be awarded?
c) One of the finalists is a friend from your town. How many of the possible finishes would include them winning a medal?
d) How many possible finishes would leave your friend out of the medal standings?