word problem

Question

The number of volunteers of a worldwide organization has increased from 5.2 million in 2004 to 11.6
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 2009
and in 2014.

Answer 1

a) The two points to determine the slope are (4, 5.2) and (10, 11.6) so slope = 6.4/6 = exactly 16/15 (or 1.07 to the hundredth place). Use point (4,5.2) in Y= m X + b to find b.  For the exact Equation, work with fractions (calculator can convert easily) so 5.2 = 26/5. Then b = 26/5 - (16/15)(4) = 14/15.  Exact Equation is   y = 16/15 x + 14/15.

b)  for 2009, x=9 so y = (16/15)(9) + 14/15 = 158/15 (10.53 to the hundredth place)
     for 2014, x=14 and y = (16/15)(14) + 14/15 = 238/15 (15.87 to the hundredth place)