William meyer bought a used car for $6,500 two years ago. he spent $1,299 for gas, $160 for oil changes, $209 for maintenance, and $200 for two new tires. he paid $657 for insurance and $158 for registration and licenses. he calculates the car has depreciated by about $2,100. william also drove the car a total of 16,789 miles and estimates that its present value is $4,400. what was the cost per mile for william to operate and maintain his car?