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A problem in mathematics is given to three students whose chances of solving it are 1/2, 1/3, 1/4 respectively. The probability that the problem is solved is

Solution

✅ Correct Option: 1

The problem involves three students attempting to solve independently with probabilities 12\frac{1}{2}, 13\frac{1}{3}, and 14\frac{1}{4} respectively.

To find the probability that at least one student solves the problem, calculate the probability that none of them solve it, then subtract from 1.


The probability each student fails:

Student 1 fails: 1−12=121 - \frac{1}{2} = \frac{1}{2}

Student 2 fails: 1−13=231 - \frac{1}{3} = \frac{2}{3}

Student 3 fails: 1−14=341 - \frac{1}{4} = \frac{3}{4}


Since the students work independently, the probability all three fail:

P(all fail)=12×23×34P(\text{all fail}) = \frac{1}{2} \times \frac{2}{3} \times \frac{3}{4}

P(all fail)=624P(\text{all fail}) = \frac{6}{24}

P(all fail)=14P(\text{all fail}) = \frac{1}{4}


The probability at least one student solves the problem:

P(problem solved)=1−P(all fail)P(\text{problem solved}) = 1 - P(\text{all fail})

P(problem solved)=1−14P(\text{problem solved}) = 1 - \frac{1}{4}

P(problem solved)=34P(\text{problem solved}) = \frac{3}{4}

Therefore, the probability that the problem is solved is 34\frac{3}{4}.

2022: 6 Aug Shift 2

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