[THOUGHT]
To find P(A), we need to calculate the probability that at least one of the three students can solve the problem. Let p1=P(S1), p2=P(S2), and p3=P(S3) be the probabilities that students S1, S2, and S3 can solve the problem, respectively.
Given probabilities:
- P(B)=P(S1∣S2∩S3)=21
- P(C)=P(S2∩S3)=101
- P(D)=P(S3)=121
From P(D)=121, we directly have:
p3=121
For P(C)=101:
P(S2∩S3)=p2(1−p3)=101
Substitute p3=121:
p2(1−121)=101
p2(1211)=101
p2=101×1112=556
For P(B)=21:
P(S1∣S2∩S3)=P(S2∩S3)P(S1∩S2∩S3)=21
First, calculate P(S2∩S3):
P(S2)=1−p2=1−556=5549
P(S3)=1−p3=1−121=1211
P(S2∩S3)=5549×1211=660539
Now, use P(B)=21:
660539P(S1∩S2∩S3)=21
P(S1∩S2∩S3)=21×660539=1320539
Since S1, S2, and S3 solve the problem independently:
P(S1∩S2∩S3)=p1(1−p2)(1−p3)=1320539
Substitute p2=556 and p3=121:
p1(5549)(1211)=1320539
p1×660539=1320539
p1=1320539×539660=21
Now, calculate P(A), the probability that at least one of the students can solve the problem:
P(A)=1−P(S1∩S2∩S3)
P(S1)=1−p1=1−21=21
P(S2)=5549
P(S3)=1211
P(S1∩S2∩S3)=21×5549×1211=1320539
P(A)=1−1320539=13201320−539=1320781
We need to simplify 1320781:
The greatest common divisor (GCD) of 781 and 1320 is 1, so the fraction is already in simplest form. Therefore, p=781 and q=1320.
Finally, calculate p2+q2:
p2+q2=7812+13202
We will use Python to ensure the arithmetic is correct.
[/THOUGHT]
[PYTHON]
p = 781
q = 1320
result = p2 + q2
print(result)