Mike, Kate, and Wendy are sick with the flu, but they still come to
school on Monday. They arrive at 8am. By 9am (Hour 1), each of them
has already infected two of his or her friends. By 10am (Hour 2), each of
Mike's, Kate's, and Wendy's friends infect two other people, meaning 12
new people have been infected by the second hour.
a. If the school day ends at 3pm, how many students in all will be
infected at the end of the school day?