At Maximum speed, an airplane travels 1680 miles against the wind in 5 hours. Flying with the wind, the plane can Travel the same distance in 4 hours.Let x be the Maximum speed of the airplane and y be the speed of the wind. what is the speed of the plane with no wind?

Answer:378 mphStep-by-step explanation:When the plane travels with the wind:Distance = 1680 milesTime = 4 hours Rate = 1681 / 4 = 420 mphWhen the plane travels against the wind:Distance = 1680 milesTime = 5 hours Rate = 1681 / 5 = 336 mphGiven the above information, we can write the equations:[tex]x+y=420[/tex][tex]x-y=336[/tex]Adding these equations to get:[tex]2x=756[/tex]x = 378 mphTherefore, 378 mph is the speed of the plane in still air.