To make a certain journey, a distance of 10 km is travelled on foot in 3 hours, a distance of 120 km is travelled by car in 3 hours, and a distance of 70 km is travelled by scooter in 4 hours. What is the average speed of the total journey?
1
50 km/h
2
35 km/h
3
45 km/h
4
20 km/h