Using the Pythagorean theorem find the length of Mountain Highway.
25^2 + x^2 = 65^2
625 + x^2 = 4225
x^2 = 4225 - 625
x^2 = 3600
x = √3600
x = 60 miles.
The total distance for Mountain highway and Oak road = 60 + 25 = 85 miles.
Airport road is shorter by 85 - 65 = 20 miles
The answer is A.