in 1990 the life expectancy of males in a certain country was 64.7 years. In 1994 it was 67.3 let E represent the life expectancy in year t and let t represent the number of years since 1990.

Question

What is the linear function E(t) that fits the data? what would the life expectancy of males be in 2009?

Answer 1

not quite enough information.
Is the increase linear or exponential?

In either case, treat your data as two ordered pairs
(0,64.7) and (4,67.3)

If linear :
slope = .65 , y-intercept is 64.7
then E = .65t + 64.7
for 2009 , t = 19
E(19) = .65(19) + 64.7 = 77

If exponential, let
E(t) = 64.7(e)^(kt)
for (4,67.3)
67.3 = 64.7e^(4k)
1.040185 = e^(4k)
4k = ln(1.040185)
k = .00985
E(t) = 64.7e^(.00985t)
E(19) = 78

(This data seems unreasonable. It would be impossible to raise the life expectancy by almost 15 years in less than 20 years)

Answer 2

math