1209 Suppose that 10 of adults belong to health clubs and 40

(12.09) Suppose that 10% of adults belong to health clubs, and 40% of these health club members go to the club at least twice a week. What percent of all adults go to a health club at least twice a week? Write the information given in terms of probabilities and use the general multiplication rule. Give your answer as a percent with one decimal place and do not include the percentage sign in your answer.

Solution

using the general multiplication rule,
P(go to health club at least twice a week)
=P(health club member)*P(go >= twice a week | health club member)
= 10% * 40%
= 4.0