<PRE><B>Question 961879</B>
an express and local train leave the station at 3pm and head for boston 50 miles away.
 the express train travels at twice the speed of the local train and arrives one hour ahead of the local train.
 find the speed of each train.
:
Let s = speed of the local
then 
2s = the speed of the express
:
Write a time equation, time = dist/speed
:
Local time - express time = 1hr
{{{50/s}}} - {{{50/(2s)}}} = 1 
multiply eq by 2s, cancel the denominators and you have
2(50) - 50 = 2s
100 - 50 = 2s
50 = 2s
s = 50/2
s = 25 mph av speed of the local
and obviously
50 mph is the speed of the express
:
:
Confirm this, find actual time of each
50/25 = 2 hrs
50/50 = 1 hr</PRE>