2 friends are 60 miles apart. They decide to ride thier bicycles to meet each other. Sally starts from the college and heads east,riding at a rate of 21 mph.At the same time Teresa starts from the river and heads west, riding at a rate of 15 mph. How far does each cyclist ride in t hours? When the cyclists meet, what must be true about the ditances they have ridden? Write and solve an equation to find when they meet.

How far did they travel in t hours?

t= distance/speed

The distance when they mey? Wont the two riders distances add to 60 miles?

This is a newer verion of a problem that is usually stated with trains.
Using distance = rate*time with time = 1hr you can see they've ridden 21 and 15 miles respectively. When they meet they should've covered the 60mi between them, correct?
Suppose they meet after time t hours of cycling, whatever time that may be. Can you see that this is somewhere between 1 and 2 hours of cycling? After 2hrs of cycling they will have met and passed each other. At time t hr they've traveled 21*t + 15*t = 60mi. Can you solve for t?