If a plane can travel 470 miles per hour with the wind and 390 miles per hour against the wind, find the speed of the wind and the speed of the plane in still air.

What is the speed of the wind? 40 mph
What is the speed of the plane in still air?

The speed of the wind is 40 mph.

To find the speed of the plane in still air, we can use the formula:

Speed of the plane in still air = (Speed with the wind + Speed against the wind) / 2

Speed of the plane in still air = (470 + 390) / 2
Speed of the plane in still air = 860 / 2
Speed of the plane in still air = 430 mph