At maximum speed, an airplane travels 2460 miles against the wind in 6 hours. Flying with the wind, the plane can travel the same distance in 5 hours, What is the speed of the plane with no wind?

451 miles per hour

distance = rate x time

against the wind this relationship is 2460 = (r-w) x 6

with the wind this relationship is 2460 = (r+w) 5

solving those two equations for r (which is the rate the plane flies) gives 902 = 2r which gives r = 451mph.