Your name and that of a friend is included in a raffle drawing. For the raffle, two tickets will be drawn, and those whose names are on the tickets win a prize. Compute the following probabilities.
1. The probability that your friend wins.
2. the probability that both you and your friend wins.
3. the probability that either you or your friend (or both) win.
4. The probability that you win but your friend does not.