Jawabanmu

2014-04-12T14:03:56+07:00
S1 = V1XT1
S1=100X1=100km
S2=V2XT2
S2=70X2
S2=140km
kelajuan rata rata = stotal/ t total
                          = 240/3
                          = 80 km/jam atau 22,2 m/s