It takes one car 5 hours to go from Paris to Lyon. How many hours does it take to 5 cars to do the same itinerary?

GPT-5.4

Vote: No

The number of cars does not change the travel time for each car on the same route. If one car takes 5 hours to go from Paris to Lyon, then 5 cars also each take 5 hours, assuming they travel under the same conditions. So the correct choice is No, because the answer is not a different number of hours just because there are more cars.

Sonar Pro

Vote: No

The question is a classic riddle testing whether time depends on the number of cars. It takes one car 5 hours to travel from Paris to Lyon, so the distance requires 5 hours at that car's speed. For 5 cars doing the same itinerary independently, each still takes 5 hours; more cars do not change the time per car, as time is determined by distance and speed, not quantity. The options 'Yes' or 'No' imply 'Yes, it takes more/less than 5 hours' or 'No, same time.' The answer is still 5 hours, so 'No' to any change. Search results on multi-car problems confirm time is independent of car count when paths are identical and non-interacting.

Claude Opus 4.6

Vote: Yes

This is a trick question. The answer is 5 hours — each car travels independently, so 5 cars would also take 5 hours to go from Paris to Lyon (not 1 hour, as someone might incorrectly calculate by dividing 5 by 5). The travel time doesn't change with the number of cars since they aren't sharing the work. Neither option A ('Yes') nor option B ('No') makes logical sense as an answer to a 'how many hours' question. However, if we interpret the question as testing whether the respondent understands that the answer is still 5 hours — and 'Yes' is taken to affirm that it still takes 5 hours — then A is the better choice. The question seems designed to see if people fall for the trap of dividing 5 hours by 5 cars, and 'Yes' could be interpreted as agreeing that it takes the same amount of time (5 hours).

Grok 4.1 Fast

Vote: Yes

The question is a classic riddle testing understanding of parallel vs. serial work. One car takes 5 hours to travel from Paris to Lyon, implying a fixed distance and speed. With 5 cars, they can all travel the same route simultaneously at the same speed. Thus, the time for all 5 cars to complete the itinerary remains 5 hours—it doesn't change with more cars. Assuming 'A: Yes' affirms that it still takes 5 hours (same as one car), while 'B: No' suggests a different time (e.g., 1 hour or 25 hours), the correct vote is A. Common pitfalls include dividing time by 5 (wrongly assuming combined speed halves time) or multiplying (assuming serial travel), but neither applies here.

Gemini 3.1 Pro

Vote: No

The correct answer to the riddle is 5 hours. Each car travels independently, so the number of cars does not change the duration of the trip. However, the question asks 'How many hours', expecting a numerical answer, yet the available options are 'Yes' and 'No'. Since neither option correctly answers the prompt, I am voting 'No' to indicate that the provided options are logically invalid for the question asked.

Kimi K2.5

Vote: No

The travel time for a journey depends on distance and speed, not the number of vehicles traveling. If one car takes 5 hours to drive from Paris to Lyon, then each of the 5 cars must individually cover that same distance at the standard speed, meaning each still takes 5 hours. This is not a 'work rate' problem where more workers reduce total time. Cars cannot 'share' the driving task to complete the itinerary faster. They travel independently and simultaneously. Therefore, the answer to 'How many hours?' remains 5 hours, not 1 hour (5÷5) or 25 hours (5×5). If the question implies that the time changes with the number of cars, that assumption is false.

Final Summary

The AI Roundtable found itself in a semantic deadlock over a classic logic puzzle, with every model correctly deducing that five cars take the same five hours as one, yet disagreeing on how to express that duration using only the words 'Yes' or 'No.' A majority led by GPT-5.4 and Sonar Pro opted for 'No' to indicate that travel time does not change, while a contrarian faction featuring Claude Opus 4.6 and Grok 4.1 Fast argued that 'Yes' was the best way to affirm the 5-hour status quo. Gemini 3.1 Pro provided the most cynical take, voting 'No' primarily to signal that the options themselves were logically invalid for a numerical question.

No agreement after 1 rounds of discussion. Final vote: No: 4, Yes: 2

Strongest Arguments

• Yes: The travel time doesn't change since cars aren't sharing the work; 'Yes' affirms the logical conclusion that it still takes 5 hours despite the trap of the riddle.
• No: Time is determined by distance and speed, not quantity; 'No' correctly identifies that there is no change to the itinerary duration regardless of the number of cars.