A gam at a fundraiser There are 20 rubber ducks floating in

A gam at a fund-raiser: There are 20 rubber ducks floating in a pool. One of the ducks has a mark on the bottom, indicating that the contestant wins a prize. Each contestant pays 25 cents to play. A contestant randomly pick 2 of the ducks. If the contestant picks the duck with the mark on the bottom, the contestant wins a prie that costs $1.

a. What is the probability that a contestant will win a prize? Explain

b. If 200 people play the game, about how many pwople would you expect to win? why?

c. Based on you answer to part (b), how much money should the duck game be expected to earn for the fund-raiser (net) if 200 people play it? Explain

Solution

a)

there are 20 ducks and only one od the ducks has a mark

so the probability that win a prize is 1/20

b)

we will use binomial distribution

1/20 * 200 = 10