Probability Problems Supplement

1. A raffle has three winning tickets in a total of 100 tickets sold. Two people each buy one ticket.

a) Since each person has a 0.03 probability of winning, together they have a 0.06 probability of winning. What is wrong with this statement?

b) Find the probability that at least one of the two people will win.

2. Two fair six-sided dice are tossed. What is the probability of at least one 3 or at least one 5 occurring on top?

3. A person draws one card from a deck. What is the probability he will draw a jack or a heart?

4. A person draws three cards from a deck. What is the probability he draws at least one jack or at least one heart? Hint: What is the complement of “at least one jack or at least one heart”?

5. A box of fruit has 50 fruits consisting of 25 good apples, 5 rotten apples, 16 good oranges, and 4 rotten oranges. A person randomly selects 4 fruits. What is the probability of selecting exactly 2 good apples or exactly 2 good oranges?

6. Six people take a 20 question test and each answers exactly one question incorrectly.

What is the probability that;

a) at least two of the six answer the same question incorrectly?

b) exactly two of the six answer the same question incorrectly? (so there are no other repeats)