During an epidemic, the number of people who have never had the disease and who are not immune (they are susceptible) decreases exponentially according to the following function, where t is time in days.
f left parenthesis t right parenthesis equals 16,000 e superscript negative 0.04 t
find the number of susceptible people at each time.
(a) at the beginning of the epidemic
(b) after 10 days
(c) after 3 weeks