There is a flu outbreak at your school that starts with 10 people. The number of ill students increases by 20% each hour. Write an exponential function to represent the total number of ill students, f(x), where x is the number of hours after the outbreak. How long does it take for at least 100 people to be ill with the flu?
a. About 10 hours
b. About 13 hours
c. About 20 hours
d. Not enough information