Stage 9 - Q10 - 8 marks
20266
For equal outward and return distances d, a rider travels at speeds \(v+w\) and \(v-w\), where \(0<w<v\), with no rest. Derive the overall average speed and show it is below v. Evaluate it for v=20, w=5 km/h and d=10 km, and find the delay compared with travelling both legs at v.
Hint
The slower return leg takes longer; use total distance divided by total time.