Question

A bus travels 120 km at 40 km/h, waits for 30 minutes, and then travels 80 km at 40 km/h. Find its average speed for the complete journey.

Solution

1. Total distance = 120 + 80 = 200 km.
2. Travelling time = 120/40 + 80/40 = 3 + 2 = 5 hours.
3. Include the 30-minute stop: total journey time = 5.5 hours.
4. Average speed = 200/5.5 = 36 4/11 km/h, approximately 36.36 km/h.