Respostas

2014-04-04T15:37:57-03:00
2014-04-04T15:50:37-03:00
Vm=ΔS/ΔT
ΔS=120-30=90
ΔT=12h-10h=2h

Substituindo na fórmula: 
Vm=90/2
Vm=45km/h