rate distance and time

Question

Two buses leave a station at the same time and travel in opposite directions. One bus travels
18

/kmh
faster than the other. If the two buses are
368km
apart after
2
hours, what is the rate of each bus?

Answer 1

One travels at a speed of s, the other at a speed of s + 18.  Since they travel in opposite directions, their relative speed is 

 

v = s + (s + 18) = 2s + 18 (km/hr)

 

At t = 2 hours, their separation distance is d = 368 km

 

Use d = vt

 

368 = (2s + 18)(2)

 

s = [368/2 - 18] / 2 = 83 km/hr

 

Then s + 18 = 101 km/hr

 

The two speeds are 83 km/hr and 101 km/hr.  You can test the solution.