Algebra
posted by Gemma on .
A turbojet flies 50 mph faster than a superprop plane. If a turbojet goes 2000 miles in 3 hours less time than it takes the superprop to go 2800 miles, find the speed of each plane.
I do not understand how to do this at all. Please explain as well as you can! Thanks.

LEt v be the velocity of the turbo plane, then v50 is the velocity of the slower. Let t be the time for turbo to go 2000 miles, then t+3 is the time for super .
(velocity*time)= distance
(v50)(t+3)=2800
and
v*t=2000
From the second equation, t=2000/v, put that into the first equation.
(v50)(2000/v + 3)=2800
multiply both sides by v
(v50)(2000+3v)=2800v
multiply it all out, gather terms, and use the quadratic equation. 
turbojet: 400mph
superprop: 350mph