Suppose that 70% of the customers at a particular fast food restaurant order a h
ID: 3150355 • Letter: S
Question
Suppose that 70% of the customers at a particular fast food restaurant order a hamburger, 50% order French fries, and 45% order both. Let H denote the event that a randomly selected customer orders a hamburger, and let F denote the event that he or she orders French fries. Use the correct probability notation. a) Convert the given percentages into probability statements involving these symbols (H, F). b) Determine the probability that a randomly selected customer orders either a hamburger or French fries. c) Determine the conditional probability that a randomly selected customer orders French fries given that he or she orders a hamburger.
Explanation / Answer
a.
P(H) = 0.70 ; P(F) = 0.50 ;P( H n F) = 0.45
b.
P( H u F) = 0.70 + 0.50 - 0.45 = 0.75
c.
P( French fries given that he or she orders a hamburger ) = P F | H ) = P( F n H) / P(H) = 0.45 / 0.70 = 0.6428