Jawabanmu

2014-09-11T17:48:22+07:00
4km/jam + 2km/jam = 6000/3600 = 1,7 m/s
2014-09-11T17:52:56+07:00
4km = 4000m/3600s
2km = 2000m/3600s
6000m/3600s