3.3 Probabilities Using Counting Methods

Ex 1 Two brothers enter a race with five friends. The racers randomly decide on starting positions. What is the probability that the older brother will start in lane 1 and the younger brother in lane 2?

Ex 2 A focus group of 3 members is to be randomly selected from a medial team consisting of five doctors and seven technicians.

(a) What is the probability that the focus group will be comprised of doctors only?

(b) What is the probability that the focus group will not be comprised of doctors only?

Ex 3 What is the probability that two or more students out of a class of 24 will have the same birthday?

p. 324#1-3, 5-10