A census reported the given table for how worker 16 years and over commute to work.

a. What is the probability that a randomly selected person carpooled to work or walked to work?

b. Given that a person carpooled to work or walked to work, what is the probability that the person carpooled to work?

Method Used To Commute___________________ Frequency

Drove alone……………............…………………………..97,129,222

Carpooled………………………….............……………….15,601,059

Public transportation…………………….......…………..6,030.791

Walked………………………………………………...............3,709,780

a. P(carpooled to work or walked to work) = ___

b. P(carpooled| carpooled or walked) = ___