Two cars leave Chicago, one traveling east and the other west. After three hours, they are 297 miles apart. If one car is traveling 5 mph faster than the other, what is the speed of each vehicle?

Question

anonymous · Answer

Let the car towards west = W
Car towards east  = E

Let E be travelling at X   MPH
The W will be travelling at x +5   mph

Because the cars are going in oppisite directions, their relative velocit is the sum their respective velocities. ( using Newtonian )
relative velocity = x +  (x +5)
In  three hours the distance  travelled is  3 * relative velocity
i. distance = 3*(x + (x+5)) = 297
=> 6x + 15  = 297
=> x =  (297 -15)/6  =  282/6  = 47

Therefore there exact speed:

47 mph

and 

52 mph