If 2 bikers had to bike 200km. One was 5km/h faster than the other...?

If 2 bikers had to bike 200km. One was 5km/h faster than the other and that person also made a 30min stop on the way to the finish. They both crossed the finish line at the same time. How would I go about completing this question? All i can get is (a=b+5) with "a" being the first biker and "b" being the second biker