The bus traveled 60 km at a speed of 40 km / h, made a stop for 30 minutes and then drove to the final

The bus traveled 60 km at a speed of 40 km / h, made a stop for 30 minutes and then drove to the final destination 54 km in 1 hour. What is the average speed of the bus?

1) Let’s find how long the bus traveled the first 60 km (at a speed of 40 km / h): t1 = S1 / v1 = (60 km) / (40 km / h) = 1.5 hours.

2) The average speed is calculated as the ratio of the total distance traveled by the bus to the total time taken by this route (even taking into account the half-hour stop). Then we have: vav. = (S1 + S2) / (t1 + t2 + t3) = (60 km + 54 km) / (1.5 h + 0.5 h + 1 h) = 114 km / 3 h = 38 km / h.

ANSWER: vav. = 38 km / h.