A, B, and C start together from the same place to walk round a circular path of length 12 km. A walks at the rate of 4 km/hr, B walks at the rate of 3 km/hr and C walks at the rate of 3/2 km/hr. They will meet together at the starting place at the end of
1
10 hours
2
12 hours
3
15 hours
4
24 hours