If an airplane is moving at velocity v, the drag D (in N ) on the plane is D = av² + b/v2, here a = 5.20 * 10-3 and b = 3.06 × 108 . Find the value(s) of v (in km/h), for which the drag is the least. Round the answer to one decimal place. Both coefficients, a and b, already account for the unit conversion (from m/s to km/h).