algebra word problem

Question

The number of volunteers of a worldwide organization has increased from
5.6
million in
2004
to
11.7
million in
2010.


(a) Find an equation for the line containing the given points. Let x represent the number of years after 2000 and y the number of volunteers, in millions.

(b) Estimate the number of volunteers in
2007 and in 2014.

Answer 1

The points (3, 5.6) and (11, 11.7) are on the line.

 

slope = (11.7-5.6)/(11-3) = 0.7625

 

Equation of line:  y - 5.6 = 0.7625(x - 3)

 

                        y - 5.6 = 0.7625x - 2.2875

 

                               y = 0.7625x + 3.3125

 

(b).  In 2009, x = 9, so y = 0.7625(9) + 3.3125 = 10.175

 

                                                                   ≈ 10.2 million

 

       In 2014, x = 14, so y = 0.7625(14) + 3.3125 = 13.9875

 

                                                                      ≈ 14.0 million