Question

Suppose that 75 percent of the people in a certain metropolitan area live in the city and 25 percent in the suburbs. If 1200 people attending a certain concert represent a random sample from the metropolitan area, what is the probability that the number of people from the suburbs attending the concert will be fewer than 270?

Answer 1

31/40

Explanation:

Probability is given by number of possible outcomes ÷ number of total outcomes

Number of possible outcomes = 270, number of total outcomes = 1200

Probability (the number of people from the suburbs attending the concert is 270) = 270/1200 = 9/40

Probability (the number of people from the suburbs attending the concert is fewer than 270) means that the number of people from the suburbs attending the concert is not 270 = 1 - 9/40 = (40-9)/9 = 31/40