Question

If a plane can travel 470mph with wind and 430mph against the wind, find the speed of the plane in still air.

What is the speed of the plane is in still air?

Answer 1

downstream = speed of plane + speed of wind
upstream = speed of plane - speed of wind

knowing these things...
let x = speed of plane
y = speed of wind

470 mph = x + y
430 mph = x - y

using systems of linear equations...

900 = 2x
x = 450 mph

is that the answer you're looking for?

Answer 2

That's I thought. But wasn't sure. Thank u