A business woman intends to rent a car for a 3 day business trip. The rental is $65 a day and $.15 per mile (plan 1) or $90 a day with unlimited mileage (plan 2). She is not sure how many miles she will drive but estimates that it will be between 400 and 800 miles.

A) For each plan find a formula for the cost C in terms of the number of a miles driven
B) Which rental plan is cheaper if she drives 400 miles?
C) Which rental plan is cheaper if she drives 800 miles?
D) At what mileage do the two plans cost the same?
Please help with all of them and show the work step by step. I want to check my answers please.

1 answer

A
plan1-cost = .15m + 195
plan2-cost = 270
where m is the number of miles

B and C, just plug in the mileages

D
set .15m + 195 = 270 and solve