Answer
For a car with 16 mpg in the city = 23.313; For a car with 28 mpg in the city = 35.709.
Work Step by Step
Use the regression line to find the predicted highway mileage for a car that gets 16 mpg in the city; do the same for a car with 28 mpg in the city:
Predicted highway mpg = 6.785 + 1.033 (16) = 23.313
Predicted highway mpg = 6.785 + 1.033 (28) = 35.709