I have to come up with a formula that meets the following conditions.

The formula is to calculate the cost of maintenance on a car. The cost of maintenance is .0375 cents per mile for the first 10,000 miles the car is driven per year, .045 cents per mile for each mile driven after those first 10,000 miles. Also the minimum maintenance cost is $300, meaning that if the car is not driven at all there should still be a maintenance cost of $300.

Any help is appreciated. Thanks