A man travels by his office bus at the speed of 54 km/h and reaches 18 minutes early. If he goes at the speed of 36 km/h, he reaches 18 minutes late. What will be the speed of the bus to reach at normal time?
1
289/5 km/h
2
512/5 km/h
3
216/5 km/h
4
192/5 km/h