Conditional probability question

Question

Eleven percent of the cars owned by a car rental firm have some defect. What is the probability that of 3 cars selected at random, the following will occur? (Round your answers to four decimal places.)

a) none has a defect

b) at least one has a defect

Answer 1

This is a binomial problem with p=.11 and q=.89.

Probability of none defective is same as all 3 have no defect, i.e. (.89)³ and

the probability of at least one with a defect is 1-the probability of none defective..