In 2005, 120 students at Lincoln High School had smart phones. By 2010, 345 students in the
same school had smart phones. Which of the
following best describes the annual rate of change
in the number of smart phones students had from
2005 to 2010 at Lincoln High School?
A) The average increase in the number of smart
phones per year is 40.
B) The average increase in the number of smart
phones per year is 45.
C) The average increase in the number of smart
phones per year is 50.
D) The average increase in the number of smart
phones per year is 55.