Reasoning · 1 checks · max 800 tokens · benched 2026-09-16
xAI models side by side on "Stacked discounts and tax": Grok 4.3 scores 10/10; Grok 4.3 is the cheapest answer scoring 8+ at $1.23 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
An item costs $250.00. A 20% discount is applied, then a $15.00 coupon is subtracted, and finally 8% sales tax is added to the resulting amount. What is the final price? Reply with only the amount in dollars to two decimal places, for example 12.34, with no currency symbol.
Rubric for the judge: The single correct answer 199.80 (250 x 0.8 = 200; 200 - 15 = 185; 185 x 1.08).
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.
x-ai/grok-4.6
293 in · 191 out (188 reasoning) · 1 words · checks 1/1
199.80
Judge: The output matches the correct answer of 199.80 in the exact format requested (two decimal places, no currency symbol).
x-ai/grok-4.5
293 in · 199 out (196 reasoning) · 1 words · checks 1/1
199.80
Judge: The output matches the correct answer of 199.80 in the exact format requested (two decimal places, no currency symbol).
x-ai/grok-4.20
273 in · 715 out (608 reasoning) · 71 words · checks 0/1
199.80 The calculation begins with the original price of 250. A 20% discount is equivalent to multiplying by 0.8, resulting in 200. Subtracting the 15 coupon yields 185. Adding 8% sales tax is performed by multiplying 185 by 1.08, which equals 199.8 (or 199.80 when formatted to two decimal places). This sequence follows the exact order of operations specified: discount first, then coupon subtraction, then tax addition on the final subtotal.
Judge: Output contains the correct numerical answer (199.80) but violates the explicit instruction to reply with only the amount, including unnecessary explanatory commentary.
x-ai/grok-4.3
279 in · 406 out (403 reasoning) · 1 words · checks 1/1
199.80
Judge: The output matches the correct answer of 199.80 in the exact format requested (two decimal places, no currency symbol).
Reasoning: The single correct answer 199.80 (250 x 0.8 = 200; 200 - 15 = 185; 185 x 1.08). The deterministic checks are exact.
If the judge's bar of 8/10 is good enough for you, Grok 4.3 at $1.23 per 1,000 runs. If you need the top score, Grok 4.3 at $1.23 per 1,000 runs.
Run it yourself
Re-run this prompt on xAI with your own OpenRouter key, or tweak the wording and see what changes.
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