Probability and coincidences help

#1
Can someone please help in the breakdown of how I do this question I am completely lost and I am not sure how to even word the answers


3. Suppose studies have shown that approximately 20% (.2) of Americans regularly engage in exercise (at least 3 times per week).

a. If one American is randomly selected, what is the probability that he or she does not regularly engage in exercise? Set up calculation.
b. If three Americans are randomly selected, what is the probability that all three regularly engage in exercise? Set up the calculation.
c. What assumption is being made in part b above?
d. If two Americans are randomly selected, what is the probability that the first American regularly engages in exercise while the second American does not regularly engage in exercise? Set up the calculation.

I am also confused on which rules to use for each one HELPPP:eek: