In 1993, the life expectancy of males in a certain country was 61.3 years. In 1999, it was 64.7 years. Let E represent the life expectancy in year t and let t represent the number of years since 1993.

Question

The linear function E(t) that fits the data is?
answer: E(t)=-0.03t+61.3

use function to predict life expectancy in 2003 61

Ok is this one right now?

Answer 1

Your equation does not produce the given data values

since you want this to be linear,
treat it as if you are given two ordered pairs
(1993,61.3) and (1999,64.7)

the slope of that is 3.4/6 or 17/30

so the equation would be
E(t) = (17/30)t + b
sub in first point
61.3 = (17/30)(1993) + b
b = -32042/30

(I tested for the second point, it works)

so E(t) = (17/30)t - 32042/30

so if t = 2003
E(2003) = (17/30)(2003) - 32042/30
= 66.97 or
= 67.0 using 3 significant digits.