Equation is
Q(x)=2000+200*cos(x*15°)
Q(0)=2000+200*cos(0°)=2200 students in 2000 year
Q(4)=2000+200*cos(60°)=2100 students in 2004 year
Q(16)=2000+200*cos(240°)=1900 students will be in 2016 year
1900 students would be in 2016 year..
13 because the scale factor is 1/3