finding average speed

Question

kester and sam cycle from the same place at the same time in opposite directions. after 2 hrs, they will be 57 km apart. if they cycle from the same place in the same direction, after 2 hrs they will kester will be 3 km ahead. what is kester's average speed?

Answer 1

Distance = (Rate)(Time)

 

Let x = Kester's Rate

 

Let y = the other cyclist's rate

 

Then, 2x + 2y = 57 and 2x = 2y + 3

 

So, 2x + 2y = 57

      2x - 2y = 3

 

4x = 60

 

x = 15 km/hr