SOLUTION: Over a distance of 120 km, the average speed of a train is 40km/h faster than that of a car. If the train covers the distance in 30min less time, find its average speed. an equa

Algebra ->  Algebra  -> Quadratic Equations and Parabolas -> SOLUTION: Over a distance of 120 km, the average speed of a train is 40km/h faster than that of a car. If the train covers the distance in 30min less time, find its average speed. an equa      Log On

Ad: You enter your algebra equation or inequality - Algebrator solves it step-by-step while providing clear explanations. Free on-line demo .
Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!
Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!

   

Question 106504: Over a distance of 120 km, the average speed of a train is 40km/h faster than that of a car. If the train covers the distance in 30min less time, find its average speed.
an equation for this pls?
thanks =D
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
let x="speed of train"

from car ... t=d/r ... t=120/(x-40)

from train ... r=d/t ... x=120/((120/(x-40))-30)