Posted by Caroleen on .
I'm having some trouble with my algebra homework. Please walk me through the question completely and give me the answer so I can fully understand it if I would ever need to solve a similar problem.
Here's the problem:
#1: Jon begins jogging at a steady 3 meters/sec down the middle of Lane #1 of a public track. Laura starts even with him in the center of Lane #2 but moves at 4 meters/sec. At the instant they begin, Ellis is located 100 meters down the track in Lane #4, and is heading towards them in his lane at 6 meters/sec. After how many seconds will the runners lie in a straight line?
a. Let t be the number of seconds the three have been running. Write expressions for the number of meters each has run after t seconds.
b. Consider the location of each runner as a point on a graph. What quantity might you use as the xcoordinate? What quantity might you use as the ycoordinate?
c. How can you tell if three points are on a line? Use this to solve the problem.
Thanks so much in advance. Any help is appreciated, even if you can only solve one part. Thanks!

Algebrahelp really needed! 
drwls,
The location of J from the starting line is 3 t. The location of L is 4t. The location of E from the starting line is 100  6t.
A straight line from J through L intersects the middle of lane 4 at a distance 6t from the starting line. (Remember that lane #3 is empty).
When 6 t = 100  6t, the runners are on a straight line.
12 t = 100
t = 8 1/3 seconds
At that time XYjon (lane 1) = 25 m; Ylaura (lane 2)= 33.33 m and Yellis (in lane 4) = 50 m
Make a plot of showing where the runners are in X (lane number) and Y (from starting line) at that time and you will see they fall along a straight line