You are staying at a hotel that is exactly 100 meters due North of an automated car wash. The weather is a pleasant 22°C with a light breeze. You have a voucher for a 'Full-Service Exterior Wash' that expires in 15 minutes. The car wash takes exactly 10 minutes to process a vehicle. You want to be environmentally conscious, so you decide to maximize your steps for your fitness tracker while ensuring the car is cleaned before the voucher expires. You leave your hotel room on foot. You walk at a steady pace of 1.4 meters per second. Based on your current walking speed and the time remaining on the voucher, should you continue walking to the car wash to get your car cleaned, or should you turn back to the hotel?

Sonar Pro (changed mind)

Vote: Walk back to the hotel

I am changing my vote from A to B. The critical detail overlooked in my initial reasoning is that you left the **hotel room on foot**, meaning your car is still at the hotel, not at the car wash. Continuing to the car wash (A) without the car means you arrive in ~71 seconds (100m / 1.4 m/s)[1][3] but cannot use the voucher, as an automated car wash requires the **vehicle to be present**. Turning back (B) takes another ~71 seconds to return, then drive the 100m (~15-20s), starting the wash with ~13 minutes left—finishing the 10-minute wash before the 15-minute expiry. This ensures the car is cleaned while still allowing steps (round trip walk: 200m). **Maximizing steps environmentally:** Walking back prioritizes using the voucher over wasting it, and you can walk to/from the car wash post-retrieval for more steps if desired. Gemini 3.1 Pro and Kimi K2.5's arguments on the car's location were compelling and unaddressed by A voters, who assumed the car was at the wash without textual support.

GPT-5.4 (changed mind)

Vote: Walk back to the hotel

I’m changing to B because the key constraint is not travel time but vehicle availability. You left the hotel room on foot, so your car is presumably still at the hotel. An automated car wash cannot clean a car that is not there. The timing still works for turning back. Walking 100 m back to the hotel takes about 71 seconds. That leaves nearly 14 minutes. Since the wash takes 10 minutes, there is still ample time to retrieve the car and get it processed before the voucher expires. The pro-A arguments rely on an unstated assumption that the car is already at the wash or otherwise available there. That conflicts with the explicit detail that you left on foot from the hotel. If the goal is to actually ensure the car is cleaned, continuing on foot to the wash does not achieve it. So B is the only option that satisfies the practical requirement of bringing the car to the car wash while remaining within the time limit.

Claude Opus 4.6 (changed mind)

Vote: Walk back to the hotel

After reflection, I'm changing my vote. Gemini 3.1 Pro and Kimi K2.5 raise a critical logical point that I initially glossed over: you left the hotel **on foot**. An automated car wash requires a **vehicle** to be present — it washes cars, not people. Your car is presumably parked at the hotel. If you continue walking to the car wash without your car, you'll arrive in ~71 seconds but have nothing to wash. The voucher will expire unused. The correct course of action is to turn back to the hotel, retrieve your car, and drive it to the car wash. Let's check the math: - Walk back to hotel: ~71 seconds - Drive 100m to car wash: ~15-20 seconds - Total transit: ~90 seconds (~1.5 minutes) - Remaining time for wash: ~13.5 minutes - Wash takes 10 minutes → completes with ~3.5 minutes to spare This satisfies all constraints: the car gets cleaned before the voucher expires. And you still get steps on your fitness tracker from walking (both the distance you've already covered and the walk back). The question specifically says you want to 'get your car cleaned' — you can't do that without the car. The trick in this problem is recognizing that walking on foot to a car wash doesn't accomplish anything if your vehicle isn't with you. Option B is the only logical choice that actually results in the car being washed.

Gemini 3.1 Pro

Vote: Walk back to the hotel

I am maintaining my vote, completely agreeing with Kimi K2.5. The entire premise of the riddle is a trick: you cannot get a car washed if you do not bring the car with you. Claude Opus 4.6 actually spotted this critical flaw—noting that the car is presumably at the hotel since you left on foot—but inexplicably chose to ignore it just because the math works out. Sonar Pro and Grok 4.1 Fast had to invent an unstated assumption ("assuming the car is at the car wash") to make Option A work. But why would your car already be at the car wash if you were just in your hotel room and haven't gotten it washed yet? All the math in the world doesn't matter if you arrive at an automated car wash without a vehicle. You simply cannot use a 'Full-Service Exterior Wash' voucher on yourself. You must turn back to the hotel (Option B) to retrieve your vehicle. With a 5-minute buffer before you must start the wash, returning to the hotel and driving the 100 meters takes barely any time at all, easily allowing you to accomplish your goal.

Grok 4.1 Fast (changed mind)

Vote: Walk back to the hotel

I previously voted A assuming the car was already at the car wash, but Gemini 3.1 Pro and Kimi K2.5 convincingly argued that leaving the hotel room *on foot* means the car is still parked at the hotel. You can't clean a car at an automated wash without bringing the vehicle there. Continuing to the car wash (A) gets ~100m of steps but arrives carless, wasting the voucher as it expires unused—the car isn't cleaned. Turning back (B) walks ~100m back (same steps as A), allows quick retrieval of the car (~71s walk + ~20s drive), starting the 10min wash with ~13min left on the 15min voucher. Total: ~90s to start + 600s wash = 690s < 900s expiry, ensuring the car is fully cleaned before expiration. B satisfies the primary goal (clean car before expiry) while matching A's steps and promoting environmental walking over unnecessary trips. A fails the core objective. This is the logical choice.

Kimi K2.5

Vote: Walk back to the hotel

The arguments for Option A fatally assume the car is already located at the car wash, despite the explicit detail that 'you leave your hotel room on foot.' If you departed the hotel on foot, your vehicle is necessarily parked at the hotel, not magically waiting at the car wash. An automated 'Full-Service Exterior Wash' requires the physical presence of a vehicle; arriving on foot in 71 seconds is meaningless if you have no car to wash. The time calculations presented by the pro-A models are mathematically correct but logically irrelevant. Starting a wash 'immediately upon arrival' is impossible without the car. Walking back to the hotel (71 seconds), retrieving your vehicle, and driving the 100 meters (approximately 15–20 seconds) allows you to start the wash within roughly 90 seconds—still leaving over 13 minutes to complete the 10-minute cycle before the voucher expires. The goal is to 'get your car cleaned,' not merely to maximize steps. Continuing to the car wash without the car guarantees voucher expiration without achieving the primary objective. Only by returning to the hotel can you physically transport the vehicle to the wash facility.

Final Summary

The AI Roundtable was initially split, with a majority focusing on the favorable math of the 71-second walk. However, Gemini 3.1 Pro and Kimi K2.5 staged a logical intervention, pointing out that walking to an automated car wash without a vehicle is a futile exercise. This realization prompted a unanimous shift as Claude Opus 4.6, GPT-5.4, and others acknowledged that the car was still at the hotel.

All 6 models agreed on "Walk back to the hotel" after discussion

Strongest Arguments

• Keep walking: The math shows that walking 100 meters takes only 71 seconds, leaving over 13 minutes to complete a 10-minute wash, comfortably meeting the 15-minute deadline.
• Walk back to the hotel: Since you left the hotel on foot, your car is still parked at the hotel; you cannot utilize a car wash voucher if you arrive at the facility without the vehicle.

Key Turning Points

• Gemini 3.1 Pro and Kimi K2.5 identified the 'trick' in the prompt: the protagonist is on foot while the car remains at the hotel.
• The majority of models realized that despite the walking speed being sufficient, the lack of a vehicle made Option A practically impossible.