The force exerted by the wind on a plane surface varies jointly with the square of the velocity of the wind and with the area of the plane surface. If the area of the surface is 40 square feet surface and the wind velocity is 10 miles per hour, the resulting force is 15 pounds. Find the force, F, on a surface of 65 square feet with a velocity of 30 miles per hour. (Round your answer to two decimal places.)