Question:
Mrs. Magdalino kept records on how much she spent on gasoline and the maintenance of her car. She found that it cost $485 to drive 500 mi in a month.
a) Find the cost per mile. Write an equation that relates the cost c for gasoline and maintenance of a car to the number of miles m the car is driven.
b) Use the equation to find the cost for driving 1200 miles.
c) About how many miles are driven for a cost of $820?
Answer:
a)
$485/500mi = $0.97/mi
c = cost
m = miles driven
cost per miles driven = cost / mile driven = c/m
b)
(1200 mi)*($0.97/mi) = $1164
c)
(x miles)*($0.97/mi) = $820
*divide both sides by $0.97/mi
x miles = $820/($0.97/mi)
x = 845.36 miles