Time it takes for him to finish:
t = 26.2/5.6 = 4.679 hours (to complete race)
.
Runner B:
Time it takes for him to finish:
t = 26.2/6.4 = 4.094 hours
BUT wait, we have to account for the extra .5 hours -- the time it took for him to cross the start line.
t = 4.094 + .5 = 4.594 hours
.
Since Runner B's time is less than Runner A's, we must conclude Runner B will finish first.