In the U. S. about 15% of the population is 65 years or older (senior citizens). It is estimated that 90% of seniors get a flu shot each year. It is also estimated that 45% of non-seniors get a flu shot. If a U. S. citizen is selected at random:
a) What is the probability they are under 65 years old?
b) What is the probability they are over 65 and did not get a flu shot?
c) What is the probability they got a flu shot?