Two trains, A and B, leave their respective starting points at the same time and travel in opposite directions. They travel at constant speeds, and pass at point M. One travels at twice the speed of the other. If one of the trains leaves five minutes late they pass at a point 2 miles from point M.

What is the speed of the slow train, in miles per hour?

(In reply to General Shortcut Formula by Jayaram S)

This shortcut works only for the specific condition that the fast train is exactly twice as fast as the slow train.

An even more general solution for trains moving towards each other would be:

Let
d = late distance (miles),
t = late time (hr),
x = Slow Train speed (miles/hr),
Kx = Fast Train speed (miles/hr)

1. Slow Train speed = x = ((1+K)/K)*(d/t) (miles/hr)
2. Fast train speed = Kx = (1+K)*(d/t) (miles/hr

Posted by Sanjay on 2003-05-18 09:03:27