Solution
Part A
For this case we have the following information given:
t= 2001 (0) f(0)= 17.5%
t= 2011 (10) f(10)= 10.3
We can calculate the slope on this way:
[tex]m=\frac{10.3-17.5}{10-0}=-0.72[/tex]Then we can do the following:
10.3 = -0.72*10 +b
b= 10.3 +10*0.72= 17.5
Then the equation is:
f(t) = -0.72t + 17.5
Part B
For 2015 the value of t = 2015-2001= 14
Replacing we got:
f(14)= -0.72*14 + 17.5= 7.42