d=36km/hx5min= 36/60km/minx5min= 36/12=3km. Inurmatoarele 5 a parcurs 45/60x5=45/12=15/4km iar in ultimele 72/60x5=72/12=6km.
b) viteza medie, timpii fiid egali este de (36+45+72)/3=153/3=51km/h. Verificam: in primul caz a parcurs( 6+3+15/4)Km=(36+15)/4=51/4km In al doilea caz 51/60x15=51/4km. Se verifica. Dci este corect!