When a new charter school opened in 1993, there were 530 students enrolled. Write a formula for the equation N, representing the number of students attending this charter school t years after 1993, assuming that the student population: N Increased by 24 students per year Decreased by 20 students per year Increased by 40 students every 2 years Decreased by 48 students every 4 years Remained constant (did not change). Increased by 10 students every semester (twice each year) N= N N N N 11