Answer:
6 hours
Explanation:
speed = distance/ time
6000meters to km = 6000/1000= 6km
speed for the first race = 6/2
speed = 3km/hr
for the second race
speed = distance/time
3 = 18/time
cross multiply
3* t = 18
divide both sides by 3
t = 18/3
t = 6 hours