Bicycle Race

Dunno, but that's one slow race!

Here's the solution:

During Robert's 15 min headstart he travels 3.5 km [Distance = Speed x Time] [0.25 hrs * 14 kph].

Added to the 500 m advantage means that he is a total distance of 4 km in front when Lionel starts.

The 'net' speed of Lionel is 3 kph (17 kph - 14 kph).

Finally, using [Time = Distance / Speed], we get: [4 km / 3 kph] which gives 1.333 hours.