Purchasing Survey asked purchasing professionals what sales traits impressed them most in a sales representative. Seventy-eight percent selected “thoroughness.” Forty percent responded “knowledge of your own product.” The purchasing professionals were allowed to list more than one trait. Suppose 27% of the purchasing professionals listed both “thoroughness” and “knowledge of your own product” as sales traits that impressed them most. A purchasing professional is randomly sampled.

a. What is the probability that the professional selected “thoroughness” or “knowledge of your own product”?

b. What is the probability that the professional selected neither “thoroughness” nor “knowledge of your own product”?

c. If it is known that the professional selected “thoroughness,” what is the probability that the professional selected “knowledge of your own product”?

d. What is the probability that the professional did not select “thoroughness” and did select “knowledge of your own product”?