A man covers half part of a certain distance at 45 km/hr. He covers 40 percent of remaining distance at the speed of 8 km/hr and covers rest of the distance at the speed of 24 km/hr. What is his average speed for the entire journey?
1
164/7 km/hr
2
144/7 km/hr
3
156/7 km/hr
4
128/7 km/hr