Question 1170495
Let B = the speed of B.  Then the speed of A will be B + 5.
If d is the distance of the race, then B + 5 = d/5 and B = 0.6d/5,
since A covers the distance d in 5 h, and B only covers 60% 
of the distance.
Solve for d:
B = d/5 - 5 = 0.6d/5 -> 0.4d = 25 -> d = 62.5 km