Since the population growth follows a linear model, we can let x be the year and y be the population and further let
x1=2005x2=2010y1=18,000y2=32,800
After which, we can use the two-point form, given as (y2-y1)/(x2-x1)=(y-y1)/(x-x1), to find the linear equation that represents the population growth. Thus,
(32,800-18,000)/(2010-2005)=(y-18,000)/(x-2005)14,800(x-2005)=5(y-18,000)14,800x-29,674,000=5y-90,0005y=14,800x-29,674,000+90,0005y=14,800x-29,584,000y=2960x-5,916,800
Thus, we can now calculate for the projected 2015 population. Substitute 2015 to x in the above equation and we have 47,600.
