(a) Find a linear function C that models the cost of driving x miles per month.?
The monthly cost of driving a car depends on the number of miles driven. Lynn found that in May her driving cost was $380 for 480 mi and in June her cost was $460 for 800 mi. Assume that there is a linear relationship between the monthly cost C of driving a car and the distance x driven.
(a) Find a linear function C that models the cost of driving x miles per month.
B.) What is the slope of the line
C.) At what rate does Lynn's cost increase for every additional mile she drives?
$ ? per mile
- L. E. GantLv 72 months agoFavorite Answer
let y represent dollars
let x represent miles
then y = mx + k for some k
slope = rise/run
rise is change in dollars = 460 - 380 = 80
run is change in miles = 800 - 480 = 320
so slope = 80/320 = 1/4
when y = 380, x = 480
so 380 = 480/4 + k
==> k = 380 - 120 = 260
when y = 460, x = 800
so 460 = 800/4 + k
==> k = 460 - 200 = 260
So C(x) = (x/4) + 260
increase in cost per mile is 0.25 dollars