Two cyclists rode. One covered 10 km, the other 6 km

Why

Kashish's instinct is reasonable if both rides took roughly the same time — cover more ground in the same time and you genuinely are faster. But she's been told only the DISTANCE, and speed is never distance alone; it's how much distance was covered in how much TIME. The 10 km cyclist could have taken three slow, resting hours, while the 6 km cyclist raced it in twenty minutes flat — in which case the shorter ride was actually far faster. Distance tells you how far someone travelled, nothing about how quickly. Test: imagine one cyclist walking their bike most of the way over a whole day to cover 10 km, versus someone sprinting 6 km in fifteen minutes — the second is unmistakably faster despite the shorter distance. No, cannot say without knowing time: speed compares distance AND time together, and distance by itself, with no time given, cannot tell you who was faster.