Question

从甲地到乙地全长60000m,汽车以30km/h的速度行驶1500m后,接着又以45km/h的速度行驶到乙地,汽车从甲地

Answer 1

S=60000m=60km,S1=1500m=1.5km,S2=S-S2=60km-1.5km=58.5km,v1=30km/h,v2=45km/h

t1=S1/v1=1.5km/30km/h=0.05h,

t2=S2/v2=58.5km/45km/h=1.3h

t=t1+t2=0.05h+1.3h=1.35h

v=S/t=60km/1.35h=44.44km/h

答：汽车从甲地到乙的平均速度为44.4km/h .