Worksheet:
Complementary Events
Name:__________________ Date: ___________________
Complementary Events a) For each problem, state the Event (E) and the Complement ( E ). b) Then, solve the problem. (Show all work.)
(#’s 4, 5, 6, 7 are dependent)
1) A survey done for Prevention magazine found that 77% of bike riders sometimes ride without a helmet. If four bike riders are chosen at random, find the probability that at least one of the riders does not wear a helmet all the time.
2) A coin is tossed five times. Find the probability of getting at least one tail.
3) The U.S. Department of Health and Human Services reports that 15% of Americans have chronic sinusitis. If five people are selected at random, find the probability that at least one has chronic sinusitis.
4) A person has six bonds, three stocks, and two mutual funds. If three investments are chosen at random, find the probability that at least one bond is chosen.
5) A newspaper advertises five different movies, three plays, and two baseball games for the weekend. If a couple selects two activities, find the probability that at least one of them is a play.
6) In an office there are four secretaries, six accountants, and two receptionists. If a committee of three is formed, find the probability that at least one secretary is chosen.
7) If four cards are chosen from a deck and not replaced, find the probability of drawing at least one king.
8) If three cards are chosen from a deck and replaced, find the probability of drawing at least one diamond.
