What is the predicted maintenance cost for a 6yearold bus wi

What is the predicted maintenance cost for a 6-year-old bus with a gasoline engine that gets driven for 900 miles per month?

The regression equation is
Maintenance cost = 165 + 13.1 Age + 0.221 Miles per month + 6.9 Gasoline

Predicted maintenance = 165+(13.1 * 6)+(0.221 * 900) + 6.9 *1 =$449.4