Help with word problem

Question

The life expectancy at birth y for females born in a certain country is given by the equation y=0.43x+73.6 , where x is the number of years after 1950.
a. Find the life expectancy for a female born in 1990.
b. Find and interpret the slope of the equation.
c. Find and interpret the y-intercept of the equation.

Answer 1

(a)    x=1990-1950 = 40

 

      y = 0.43*40 + 73.6 = 90.8

 

(b) The slope is M=0.43; the life expectancy increases by 0.43 every year

 

(c) The y-intercept is B=73.6, which was the life expectancy as of 1950 (x=0)