Word Problem

Question

The population of a small town in central Florida has shown a linear decline in the years 1991-2001. In 1991 the population was 48900 people. In 2001 it was 40500 people.

A) Write a linear equation expressing the population of the town, P, as a function of t, the number of years since 1991.

 

B) If the town is still experiencing a linear decline, what will the population be in 2006?

Answer 1

(a)        (1991, 48900)

           (2001, 40500)

 

     slope M = (40500 - 48900)/(2001 - 1991) = -8400/10 = -840

 

     y = Mx + b

    48900 = (-840)(1991) + b

    48900 + 840*1991  =b

 1721340 = b

 

   y = -840 x + 1721340

 

(b)  1721340 - 840*2006 = 36300