Reasoning · 1 checks · max 800 tokens · benched 2026-09-16
Anthropic models side by side on "When does the faster train catch up?": Claude Sonnet 4.6 scores 10/10; Claude Sonnet 4.6 is the cheapest answer scoring 8+ at $0.38 per 1,000 runs. Outputs, checks, judge reasons, latency and cost.
System
Think carefully, then give only the final answer in the requested format.
User
Train A leaves a station at 09:10 travelling at a constant 80 km/h. Train B leaves the same station on the same track at 09:40 travelling at a constant 120 km/h in the same direction. How many minutes after 09:10 does train B catch up with train A? Reply with only the whole number of minutes.
Rubric for the judge: The single correct answer 90, with no working shown in the final output.
Every cell is one OpenRouter call at temperature 0 with the prompt's token cap and reasoning effort "low" where the model supports it. Cost is usage × the catalogue rate in models.json. Quality is one judge call to anthropic/claude-haiku-4.5 against the prompt's rubric, cached per prompt version.
anthropic/claude-opus-5
127 in · 59 out (56 reasoning) · 1 words · checks 1/1
90
Judge: The output is exactly '90' with no extraneous commentary, matching the rubric requirement perfectly.
anthropic/claude-sonnet-5
127 in · 69 out (66 reasoning) · 1 words · checks 1/1
90
Judge: The output is exactly '90' with no extraneous commentary, matching the rubric requirement perfectly.
anthropic/claude-sonnet-4.6
102 in · 5 out · 1 words · checks 1/1
90
Judge: The output is exactly '90' with no extraneous commentary, matching the rubric requirement perfectly.
anthropic/claude-haiku-4.5
101 in · 310 out · 166 words · checks 0/1
I need to find when Train B catches up with Train A. **Setup:** - Train A: leaves at 09:10, speed = 80 km/h - Train B: leaves at 09:40, speed = 120 km/h - Train B leaves 30 minutes after Train A **Distance of Train A when Train B starts:** In 30 minutes, Train A travels: 80 km/h × 0.5 h = 40 km **Relative speed:** Train B is catching up at: 120 - 80 = 40 km/h **Time for Train B to catch up:** Time = Distance / Relative speed = 40 km / 40 km/h = 1 hour = 60 minutes **Time after 09:10:** Train B starts 30 minutes after 09:10 and takes 60 minutes to catch up. Total time after 09:10 = 30 + 60 = 90 minutes **Verification:** - Train A position at 90 minutes: 80 × (90/60) = 80 × 1.5 = 120 km - Train B position at 60 minutes after 09:40: 120 × (60/60) = 120 km ✓ 90
Judge: The answer of 90 is correct, but the rubric explicitly requires 'only the whole number of minutes' with 'no working shown in the final output', and the model provided extensive working before the answer.
Reasoning: The single correct answer 90, with no working shown in the final output. The deterministic checks are exact.
If the judge's bar of 8/10 is good enough for you, Claude Sonnet 4.6 at $0.38 per 1,000 runs. If you need the top score, Claude Sonnet 4.6 at $0.38 per 1,000 runs.
Run it yourself
Re-run this prompt on Anthropic with your own OpenRouter key, or tweak the wording and see what changes.
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