1. A coin is tossed 10 times. What is the probability of obtaining four heads and six tails?
2. A coin is tossed seven times. What is the probability of obtaining five heads and two tails?
3. A university admissions office randomly assigns each student from a group of four incoming freshmen to an orientation team. If there are seven orientation teams, what is the probability that two or more of these students are assigned to the same team?
4. An elevator has six buttons: L, 1, 2, 3, 4, and 5. Suppose that five people get on the elevator at the Lobby. What is the probability that they are each going to a different floor? Assume that each of the floors 1 through 5 is equally likely.