YMMV but I just asked the same question to both and GPT-4 calculated 9.64 laps, and mentioned how you cannot complete a fraction of a lap, so it rounded down and then calculated 24.5L.

Bard mentioned something similar but oddly rounded up to 10.5 laps and added a 10% safety margin for 30.8L.

In this case bard would finish the race and GPT-4 would hit fuel exhaustion. Thats kind of the big issue with LLMs in general. Inconsistent.

In general I think gpt-4 is better overall but it shows both make mistakes, and both can be right.