Question

If a plane can travel 490 miles per hour with the wind and 430 miles per hour against the​ wind, find the speed of the wind and the speed of the plane in still air.

Answer 1

let the speed of plane in still air be x and that wind be y

therefore:

x+y=490

x-y=390

next we solve for the values of x and y, first we add the above equations. This will give us:

2x=880

x=880/2

x=440 miles per hour.

substituting the value of x in one of the equations and solving for y we get:

440+y=490

y=490-440

y=50 miles per hour