help im stuck on my precalclus hw

Question

A car rental company offers two plans for renting a car:

Plan A: 30 dollars per day and 18 cents per mile

Plan B: 50 dollars per day with free unlimited mileage

For what range of miles will plan B save you money for a 1 day rental?

To save money the mileage must be greater than    miles per day.

Give your answer accurate to at least one decimal place

Answer 1

C = 30 + .18M = 50

.18M = 20

M = 20/.18 = 10/.09 = 111.1 miles makes the two plans the same cost

Go more than 111.1 miles in one day and Plan B is cheaper

30 + 0.18(111.1) = 50

0.18 x 111 1/9 = 19.98 + .18(1/9) = 19.98 + .02 = 20