A study by the National Park Service revealed that 50 percent of vacationers going to the Rocky

A study by the National Park Service revealed that 50 percent of vacationers going to the Rocky Mountain region visit Yellowstone Park, 40 percent visit the Tetons, and 35 percent visit both.
a. What is the probability a vacationer will visit at least one of these attractions?
b. What is the probability 35 called?
c. Are the events mutually exclusive? Explain.