maths
posted by gf on .
A passenger plane and a jest leave at the same time from the same airport, traveling in opposite directions. The jet travels at twice the speed of the passenger plane. They are 2400 miles apart in 4 hours. Find the speed of the passenger plane and jet.

Let the speed of the passenger plane be x mph, then the speed of the jet is 2x mph
The both went for 4 hours, so the
passenger plane went 4x miles
the jet went 4(2x) or 8x miles
So isn't 4x+8x = 2400 ???
etc.