Bonjour,
On va utiliser la formule :
v = d / t
1ère partie :
t = 20 min = 20/60 = 2/6 = 1/3 h
d = 10 km
v = 10/(1/3)
v = 30 km/h
2ieme partie :
t = (40 - 20) = 20 min = 1/3 h
d = 30 - 10 = 20 km
v = 20/(1/3)
v = 60 km/h
3ieme partie :
t = 70 - 40 = 30 min = 30/60 = 1/2 = 0,5 h
d = 45 - 30 = 15 km
v = 15/0,5
v = 30 km/h
4ieme partie :
t = 90 - 70 = 20 min = 1/3 h
d = 50 - 45 = 5 km
v = 5/(1/3)
v = 15 km/h
