Travelling Trains

From: Anonymous
Date: Sun, 6 Nov 1994 21:06:23 -0700 (MST)
Subject: Dr. Math & trains

Dr. Math, glad to see that you are on-line.  Where were you when I 
needed you? Is this for real?  I received a note saying that you were 
looking for math questions from students who had math problems.  
True?  I've always wondered about those two trains that left the East 
coast and the West coast.  The question asked when they would meet 
or where they would  meet if both left at the same time and were 
traveling at 60 to 70 mph. I know that isn't the exact question, but that 
has always stuck in the back of my mind.  Care to try and figure out 
some kind of reply, even though the question is sort of hazy?

Looking forward to hearing from you.

I teach Spanish here at Madison Middle School in Albuquerque, New 
Mexico. Hasta la vista.
Brian E. Tafoya

Date: Mon, 7 Nov 1994 21:35:07 +0000
From: Elizabeth Anna Weber

Hi Brian!

     Yes, we are for real.  Our main patients are K-12 students and their
teachers, but thanks for writing to us anyway!   

     If a train leaves the West Coast going at any speed, and another train
leaves the East Coast at the same time, going at the same speed, the trains
will meet in the middle.  The exact meeting point depends on the exact
starting points, but it will be somewhere on a line drawn from Texas to the
Dakotas.  The problem gets a little more complicated when the trains 
make a few stops, go at different speeds, or when the tracks don't go in a
straight line from coast to coast.

Elizabeth, Math Doctor on duty.