How are the size of a firm (measured in terms of the number of employees) and the type of firm related?

To help answer the question, an analyst referred to the U.S. Census and developed the following table of joint probabilities.

Industry Number of Employees Construction Manufacturing Retail Fewer than 20 .464 .147 .237 20 to 99 .039 .049 .035 100 or more .005 .019 .005

(Source: Statistical Abstract of the United States, 2009, Table 737.)

If one firm is selected at random, find the probability of the following events.

a. The firm employs fewer than 20 employees.

b. The firm is in the retail industry.

c. A firm in the construction industry employs between 20 and 99 workers.