Health risks to beachgoers. According to a University of Florida veterinary researcher, the longer a beachgoer sits in wet sand or stays in the water, the higher the health risk (University of Florida News, Jan. 29, 2008). Using data collected at Fort Lauderdale, Hollywood, and Hobie Beach, the researcher discovered the following: (1) 6 out of 1,000 people exposed to wet sand for a 10-minute period will acquire gastroenteritis; (2) 12 out of 100 people exposed to wet sand for two consecutive hours will acquire gastroenteritis; (3) 7 out of 1,000 people exposed to ocean water for a 10-minute period will acquire gastroenteritis; and, (4) 7 out of 100 people exposed to ocean water for a 70-minute period will acquire gastroenteritis.

a. If a beachgoer spends 10 minutes in the wet sand, what is the probability that he or she will acquire gastroenteritis?

b. If a beachgoer spends two hours in the wet sand, what is the probability that he or she will acquire gastroenteritis?

c. If a beachgoer spends 10 minutes in the ocean water, what is the probability that he or she will acquire gastroenteritis?

d. If a beachgoer spends 70 minutes in the ocean water, what is the probability that he or she will acquire gastroenteritis?