reasoning · 2026-09-23

Two trains travel in the same direction at constant speeds. The first leaves at 60 mph. One hour later, the second leaves the same station on a parallel track at 80 mph. How many hours after the SECOND train leaves does it catch the first?

Answer: a

When the second train leaves, the first train has a 60-mile head start. The second train closes this gap at a relative speed of 20 mph (80 - 60). 60 miles / 20 mph = 3 hours.

Model answers

• gpt-oss-20b (openai/gpt-oss-20b): a
• qwen-3-8-27b (qwen/qwen3.8-27b): a
• nemotron-3-super (nvidia/nemotron-3-super-120b-a12b:free): a
• gemini-3-8-flash (gemini-3.8-flash-low): a
• gemini-3-1-pro (gemini-3.1-pro-high): a
• claude-opus-4-6 (claude-opus-4-6-thinking): a