Problem Analysis #11

A.X-4.0 (72B) · Run 1

26.71s
5,008 toks
Problem Statement

Three students S1S_1, S2S_2, and S3S_3 are given a problem to solve. Consider the following events:AA: At least one of S1S_1, S2S_2, and S3S_3 can solve the problem,BB: S1S_1 can solve the problem, given that neither S2S_2 nor S3S_3 can solve the problem,CC: S2S_2 can solve the problem and S3S_3 cannot solve the problem,DD: S3S_3 can solve the problem.For any event EE, let P(E)P(E) denote the probability of EE. If

P(B)=12,P(C)=110,andP(D)=112,P(B) = \frac{1}{2}, \quad P(C) = \frac{1}{10}, \quad \text{and} \quad P(D) = \frac{1}{12},

and P(A)=pqP(A) = \dfrac{p}{q} where pp and qq are coprime positive integers, find the value of p2+q2p^2 + q^2.\

Ground Truth
19441
Execution Trace
Reasoning Process

[THOUGHT] To find P(A)P(A), we need to calculate the probability that at least one of the three students can solve the problem. Let p1=P(S1)p_1 = P(S_1), p2=P(S2)p_2 = P(S_2), and p3=P(S3)p_3 = P(S_3) be the probabilities that students S1S_1, S2S_2, and S3S_3 can solve the problem, respectively.

Given probabilities:

  • P(B)=P(S1S2S3)=12P(B) = P(S_1 \mid \overline{S_2} \cap \overline{S_3}) = \frac{1}{2}
  • P(C)=P(S2S3)=110P(C) = P(S_2 \cap \overline{S_3}) = \frac{1}{10}
  • P(D)=P(S3)=112P(D) = P(S_3) = \frac{1}{12}

From P(D)=112P(D) = \frac{1}{12}, we directly have:

p3=112p_3 = \frac{1}{12}

For P(C)=110P(C) = \frac{1}{10}:

P(S2S3)=p2(1p3)=110P(S_2 \cap \overline{S_3}) = p_2 (1 - p_3) = \frac{1}{10}

Substitute p3=112p_3 = \frac{1}{12}:

p2(1112)=110p_2 \left(1 - \frac{1}{12}\right) = \frac{1}{10} p2(1112)=110p_2 \left(\frac{11}{12}\right) = \frac{1}{10} p2=110×1211=655p_2 = \frac{1}{10} \times \frac{12}{11} = \frac{6}{55}

For P(B)=12P(B) = \frac{1}{2}:

P(S1S2S3)=P(S1S2S3)P(S2S3)=12P(S_1 \mid \overline{S_2} \cap \overline{S_3}) = \frac{P(S_1 \cap \overline{S_2} \cap \overline{S_3})}{P(\overline{S_2} \cap \overline{S_3})} = \frac{1}{2}

First, calculate P(S2S3)P(\overline{S_2} \cap \overline{S_3}):

P(S2)=1p2=1655=4955P(\overline{S_2}) = 1 - p_2 = 1 - \frac{6}{55} = \frac{49}{55} P(S3)=1p3=1112=1112P(\overline{S_3}) = 1 - p_3 = 1 - \frac{1}{12} = \frac{11}{12} P(S2S3)=4955×1112=539660P(\overline{S_2} \cap \overline{S_3}) = \frac{49}{55} \times \frac{11}{12} = \frac{539}{660}

Now, use P(B)=12P(B) = \frac{1}{2}:

P(S1S2S3)539660=12\frac{P(S_1 \cap \overline{S_2} \cap \overline{S_3})}{\frac{539}{660}} = \frac{1}{2} P(S1S2S3)=12×539660=5391320P(S_1 \cap \overline{S_2} \cap \overline{S_3}) = \frac{1}{2} \times \frac{539}{660} = \frac{539}{1320}

Since S1S_1, S2S_2, and S3S_3 solve the problem independently:

P(S1S2S3)=p1(1p2)(1p3)=5391320P(S_1 \cap \overline{S_2} \cap \overline{S_3}) = p_1 \left(1 - p_2\right) \left(1 - p_3\right) = \frac{539}{1320}

Substitute p2=655p_2 = \frac{6}{55} and p3=112p_3 = \frac{1}{12}:

p1(4955)(1112)=5391320p_1 \left(\frac{49}{55}\right) \left(\frac{11}{12}\right) = \frac{539}{1320} p1×539660=5391320p_1 \times \frac{539}{660} = \frac{539}{1320} p1=5391320×660539=12p_1 = \frac{539}{1320} \times \frac{660}{539} = \frac{1}{2}

Now, calculate P(A)P(A), the probability that at least one of the students can solve the problem:

P(A)=1P(S1S2S3)P(A) = 1 - P(\overline{S_1} \cap \overline{S_2} \cap \overline{S_3}) P(S1)=1p1=112=12P(\overline{S_1}) = 1 - p_1 = 1 - \frac{1}{2} = \frac{1}{2} P(S2)=4955P(\overline{S_2}) = \frac{49}{55} P(S3)=1112P(\overline{S_3}) = \frac{11}{12} P(S1S2S3)=12×4955×1112=5391320P(\overline{S_1} \cap \overline{S_2} \cap \overline{S_3}) = \frac{1}{2} \times \frac{49}{55} \times \frac{11}{12} = \frac{539}{1320} P(A)=15391320=13205391320=7811320P(A) = 1 - \frac{539}{1320} = \frac{1320 - 539}{1320} = \frac{781}{1320}

We need to simplify 7811320\frac{781}{1320}: The greatest common divisor (GCD) of 781 and 1320 is 1, so the fraction is already in simplest form. Therefore, p=781p = 781 and q=1320q = 1320.

Finally, calculate p2+q2p^2 + q^2:

p2+q2=7812+13202p^2 + q^2 = 781^2 + 1320^2

We will use Python to ensure the arithmetic is correct. [/THOUGHT] [PYTHON] p = 781 q = 1320 result = p2 + q2 print(result)

Tool Output
[PYTHON OUTPUT] 2352361 [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] Based on the Python output, the value of p2+q2p^2 + q^2 is 2352361. Therefore, the final answer is: 2352361\boxed{2352361}

Final Model Output
2352361

Comparative Analysis (P11) (Average across runs)

Avg Time Taken

K-EXAONE-236B-A23B
239.9
Gemini-3-Pro-Preview
228.5
K-EXAONE-236B-A23B
110.7
Llama-VARCO-8B-Instruct
51.6
Kanana-2-30B-Thinking
51.1
Kanana-2-30B-Thinking-2601
45.9
Deepseek-V3.2
43.4
Solar-Open-100B
40.1
HCX-007(high)
39.0
Solar-Pro-2 (31B)(high)
33.7
A.X-4.0 (72B)
26.7
GPT-5.1 (high)
18.1
Grok-4.1-fast
18.1
GPT-5.2 (high)
16.9
Claude-Opus-4.5
16.1
EXAONE-4.0.1-32B (high)
5.8

Avg Token Usage

K-EXAONE-236B-A23B
27,427
Gemini-3-Pro-Preview
10,703
Kanana-2-30B-Thinking-2601
10,671
Kanana-2-30B-Thinking
10,625
Solar-Open-100B
8,808
K-EXAONE-236B-A23B
8,679
Grok-4.1-fast
8,474
Solar-Pro-2 (31B)(high)
6,509
A.X-4.0 (72B)
5,008
Deepseek-V3.2
4,986
HCX-007(high)
4,852
EXAONE-4.0.1-32B (high)
4,557
Claude-Opus-4.5
4,549
GPT-5.2 (high)
3,857
GPT-5.1 (high)
3,536
Llama-VARCO-8B-Instruct
2,394