Two cars are going opposite directions on a highway. One car is driving 4mph faster than the other car. Afte 3hr the cars are 414mi apart. Find speed of both

Question

Show me the steps to solving this equation please! 

Answer 1

The magnitudes of the 2 speeds are u and v, going in opposite directions.  Let u be the faster one.

 

Relative speed is u + v.

 

(u + v)(3 hrs) = 414 mi

u - v = 4 mph

 

Solve for u and v in

 

3u + 3v = 414

u - v = 4

 

and get

 

u = 71 mph

v = 67 mph