Question 718025
If a plane can travel 500 miles per hour with the wind and 420 miles per hour against the wind, what is the speed of the plane in still air?
***
let x=speed of the plane in still air
let c=speed of the wind
..
x+c=500
x-c=420
2x=920
x=460
c=500-x=40
speed of the plane in still air=460 mph
speed of the wind=40 mph