The freshman class has 160 students. Each freshman must write three reports from a list of 12 novels that the teacher has assigned them to read. How many different combinations of novels can a freshman student choose to write reports on?
each student can write #12# choose #3# possible combination of reports which is #(n!)/((n-k)!k!) = 220# . It seems a bit necessary to mention the class size but perhaps that was to test your knowledge.