Question

In 1990, the life expectancy of males in a certain country was 64.7 years. In 1994, it was 68.4 years. Let E represent the life expectancy in year t and let t represent the number of years since 1990.

The linear function E(t) that fits the data is

E(t)= ___t + ____
(round to the nearest tenth).

Use the function to predict the life expectancy of males in 2009.

E(19)=____
(round to the nearest tenth)

Answer 1

E(0) = 0 + 64.7
E(4) = m(4)+64.7 = 68.4
m = (68.4-64.7)/4 = .925 or .93 to tenth
so
E(t) = .93 t + 64.7

2009 - 1990 = t = 19
E(19) = .93 (19) + 64.7
E(19) = 82.4