A truck travels for 34.1 minutes at a speed of 53.5 km/h and then for 55.7 minutes at a speed of 97.9 km/h. What is the average speed of the truck?

53.5 km / hour for 34.1 minutes (34.1 / 60 = 0.5683333333 hours)

97.9 km / hour for 55.7 minutes (55.7 / 60 = 0.9283333333 hours)

53.5 *.5683333333 = 30.4058333333 kilometers

97.9 * 0.9283333333 = 90.8838333333 kilometers

Total Time = 0.5683333333 + 0.9283333333 = 1.4966666667 hours

Total Distance = 30.4058333333 + 90.883833333 = 121.2896666667 km

Avg Speed = 121.2896666667 km / 1.4966666667 = 81.0398663697 km/hour