Question

1. There are three brands, say X, Y and Z of an item available in the market. A consumer chooses exactly one of them for his use. He never buys two or more brands simultaneously. The probabilities that he buys brands X, Y and Z are 0.20, 0.16 and 0.45, respectively.
a) What is the probability that he does not buy any of the brands?
b) Given that a customer buys some brand, what is the probability that he buys brand X?