2). Mobilul a facut in 50' (11h10' - 10h20') 45 km (65km - 20km). Deci in 60 minute va face distanta de 45km : 50' × 60' = 54 km si inseamna ca are viteza de 54km/h
3). 25' inseamna 25 x 60 = 1500 s. Cu viteza de 30m/s in acest timp va parcurge
S = Vt = 30m/s x 1500 s = 45 000m = 45km.