PreAlgebra
posted by Carol on .
Question is: What is the algebraic equation to determine when they will meet?
For the following information, I understand 5(x+y) = 3000 for 1st plane & 10(xy) = 3000 for 2nd plane.
When an airplane flies with a given wind, it can travel 3000 km in 5hrs. When the same airplane flies in the opposite direction against the wind it takes 10hrs to fly the same distance. Find the speed of the plane in still air and the speed of the wind.

Vp + Vw = 3000km/5h = 600km/h.
Vp  Vw = 3000km/10h = 300km/h.
Add the 2 Eqs:
Eq1: Vp + Vw = 600.
Eq2: Vp  Vw = 300.
Sum: 2Vp = 900,
Vp = 450km/h = Speed in still air
In Eq1, substitute 450 for Vp:
450 + Vw = 600,
Vw = 150km/h. = Speed of wind.