A survey of 221 people in an introductory math course at the University of Alberta found that 173 people were under the age of 20, and 25 people were over the age of 30.

Question

(Round all answers to 3 decimal places, if needed)

a) What is the probability that a randomly selected person is either above the age of 30 or under the age of 20?

b) What is the probability that a randomly selected person is between the ages of 20 and 30, inclusive?

Answer 1

P(above 30 or under 20) = P(above 30) + P(under 20) = 173/221 + 25/221 = 198/221

P(between 20 and 30) = 1 - P(above 30 or under 20) = 22/221