SOLUTION: An express and local train leave gray's lake at 3 P.M. and head for chicago 50 miles away. The express travels twice as fast as the local and arrives 1 hour ahead of it. Find the

Algebra ->  Linear-equations -> SOLUTION: An express and local train leave gray's lake at 3 P.M. and head for chicago 50 miles away. The express travels twice as fast as the local and arrives 1 hour ahead of it. Find the      Log On


   

Question 149100: An express and local train leave gray's lake at 3 P.M. and head for chicago 50 miles away. The express travels twice as fast as the local and arrives 1 hour ahead of it. Find the speed of each train.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
an express and local train leave Gray's Lake at 3 P.M. and head for Chicago 50 miles away. The express travels twice as fast as the local, and arrives 1 hour ahead of it. Find the speed of each train.
:
The time they left is irrelevant to the problem
:
Let s = speed of the local
then
2s = speed of the express
:
Write a time equation: Time = dist%2Fspeed
:
Express time + 1 hr = Local time
50%2F%282s%29 + 1 = 50%2Fs
Get rid of the denominators, mult equation by 2s; results:
50 + 2s = 2(50)
2s = 100 - 50
2s = 50
s = 50%2F2
s = 25 mph speed of the local
then
50 mph speed of the express
;
;
Check solution
50%2F50 + 1 = 50%2F25
1 + 1 = 2