A research company has investigated buying habits of custome

A research company has investigated buying habits of customers of a local convenience store. Assume that each costumer\'s purchase is independent of each other\'s. The probability that a customer purchases a soft drink is 80%. the probability that a customer purchases a candy bar is 75%.

1. what is the probability of a customer purchasing both a soft drink AND a candy bar?

2. what is the probability of a customer purchasing a soft drink OR candy bar?

3. what is the probability of a customer purchasing neither a soft drink NOR candy bar?

Solution

events are independent

a. purchase both, probability = P(A)P(B) = 0.8*0.75 = 0.6

b. P(A or B ) = P(A) + P(B) - P(A and B ) = 0.8 +0.75 - 0.6 = 0.95

c . nothing = P(A\')P(B\') = 0.2*0.25 = 0.05