A store manager gathers some demographic information from the store's customers. The following chart summarizes the age-related information they collected:
Age Number of Customers
<20 54
20−29 80
30−39 76
40−49 59
50−59 94
≥60 68
One customer is chosen at random for a prize giveaway.
a. What is the probability that the customer is at least 40 but no older than 59?
b. What is the probability that the customer is either older than 50 or younger than 30?
c. What is the probability that the customer is at least 50?