Problem Analysis #common_06

Motif 3 · Run 1

Python ● execution succeeded
Correct
21.57s
6,635 toks

Infron · Motif 3 · 46문항 × 3회 · Python TAR. 131,072 output tokens · 기본 1,800초 · 6+1 turns. ACC는 전체 138회, Pass@1은 각 문항의 첫 유효 시도, Pass@3는 3회 내 정답으로 계산합니다.

Problem Statement

1보다 큰 두 실수 a,ba,b가 log⁡ab=3\log_a b=3, log⁡3ba=12\log_3\frac ba=\frac12를 만족시킬 때, log⁡9(ab)\log_9(ab)의 값은?

① 38\frac38 ② 12\frac12 ③ 58\frac58 ④ 34\frac34 ⑤ 78\frac78

최종 답은 선택지 번호 1~5 중 하나를 \boxed{} 안에 쓰세요.

Ground Truth
2
Recorded model response / solution
Reasoning Process

Recorded Python call:

import sympy as sp

a = sp.symbols('a', positive=True, real=True)
# b = a^3 from log_a b = 3
# b/a = sqrt(3) from log_3(b/a)=1/2
# => a^3/a = a^2 = sqrt(3)
sol_a = sp.solve(a**2 - sp.sqrt(3), a)
print("possible a:", sol_a)

a_val = sol_a[1]  # positive root > 1
b_val = a_val**3
ab = a_val * b_val
print("a:", a_val)
print("b:", b_val)
print("ab:", sp.simplify(ab))
print("log_9(ab):", sp.simplify(sp.log(ab, 9)))

Tool Output
Execution failed possible a: [3**(1/4)] list index out of range
Reasoning Process

Recorded Python call:

a_val = 3**(sp.Rational(1,4))
b_val = a_val**3
ab = a_val * b_val
print("ab simplified:", sp.simplify(ab))
print("log_9(ab):", sp.simplify(sp.log(ab, 9)))

Tool Output
Execution failed name 'sp' is not defined
Reasoning Process

Recorded Python call:

import sympy as sp
a_val = 3**(sp.Rational(1,4))
b_val = a_val**3
ab = a_val * b_val
print("ab simplified:", sp.simplify(ab))
print("log_9(ab):", sp.simplify(sp.log(ab, 9)))
Tool Output
Execution succeeded ab simplified: 3 log_9(ab): 1/2
Reasoning Process

주어진 조건에서

log⁡ab=3  ⟹  b=a3\log_a b=3 \implies b=a^3

또

log⁡3ba=12  ⟹  ba=31/2=3\log_3\frac ba=\frac12 \implies \frac ba=3^{1/2}=\sqrt3

이므로

a3a=a2=3\frac{a^3}{a}=a^2=\sqrt3

따라서

a=31/4,b=a3=33/4a=3^{1/4},\qquad b=a^3=3^{3/4}

이고,

ab=a4=(31/4)4=3ab=a^4=(3^{1/4})^4=3

따라서

log⁡9(ab)=log⁡93=12\log_9(ab)=\log_9 3=\frac12

Python 검증:

import sympy as sp
a = 3**sp.Rational(1,4)
b = a**3
sp.simplify(sp.log(a*b, 9))  # 1/2

정답은 ②번이다.

2\boxed{2}
Final Model Output
2

Comparative Analysis (Pcommon_06) (Average across runs)

Averages use reported measurements only. Missing usage is not treated as zero.

Avg Time Taken

Union Alpha
87.6
Motif 3
59.6
Grok 4.7
38.9
MiMo V2.6 Pro
19.9
Muse Spark 1.3
11.5
Solar Pro 4
8.7
DeepSeek V4.1 Flash
4.2
Solar Mini 4 Preview
3.4

Avg Token Usage

Muse Spark 1.3
6,137
Grok 4.7
6,067
Union Alpha
5,169
Motif 3
4,942
MiMo V2.6 Pro
2,646
DeepSeek V4.1 Flash
2,595
Solar Mini 4 Preview
2,496
Solar Pro 4
1,372
    CSAT 2026 · Problem common_06 · Motif 3 | EntropyMath