Question 24
Lean cycles at constant speed from A toward B. When he has travelled $5/17$ of AB, he hears a car approaching from behind at 391 km/h. If he immediately turns back, he meets it at A; if he continues forward, it catches him at B. Find Lean’s speed in km/h. In the diagram, C is the car’s position at that instant, $CA=x$ and $AB=d$.
