reasoning · 2026-10-08

Four people enter a room and each person shakes hands with everyone else exactly once. What is the total number of handshakes that occur?

Answer: b

The first person shakes hands with 3 others. The second person shakes with the remaining 2. The third person shakes with the final 1. Total = 3 + 2 + 1 = 6. (Or 4 choose 2).

Model answers

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