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A die is rolled and showing any number i...

A die is rolled and showing any number is directly proportional to that number. If prime number appears then a ball is chosen from urn `A` containing 2 white and 3 black balls otherwise a ball is chosen from urn `B` containing 3 white and 2 black balls Then.
If white ball is draw then the probability that it is from urn `B`

A

`52/53`

B

`1/53`

C

`20/53`

D

`33/53`

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The correct Answer is:
To solve the problem step by step, we will use the concepts of probability and Bayes' theorem. ### Step 1: Determine the probabilities of rolling a die The probability of rolling a number on a die is directly proportional to that number. Therefore, we can express the probabilities as follows: - Let \( P(1) = k \) - Let \( P(2) = 2k \) - Let \( P(3) = 3k \) - Let \( P(4) = 4k \) - Let \( P(5) = 5k \) - Let \( P(6) = 6k \) The sum of all probabilities must equal 1: \[ k + 2k + 3k + 4k + 5k + 6k = 1 \] ### Step 2: Solve for \( k \) Combining the terms gives: \[ 21k = 1 \implies k = \frac{1}{21} \] Now we can find the individual probabilities: - \( P(1) = \frac{1}{21} \) - \( P(2) = \frac{2}{21} \) - \( P(3) = \frac{3}{21} \) - \( P(4) = \frac{4}{21} \) - \( P(5) = \frac{5}{21} \) - \( P(6) = \frac{6}{21} \) ### Step 3: Identify the prime numbers The prime numbers on a die are 2, 3, and 5. We need to calculate the probability of rolling a prime number: \[ P(\text{prime}) = P(2) + P(3) + P(5) = \frac{2}{21} + \frac{3}{21} + \frac{5}{21} = \frac{10}{21} \] ### Step 4: Calculate the probability of rolling a non-prime number The probability of rolling a non-prime number is: \[ P(\text{not prime}) = 1 - P(\text{prime}) = 1 - \frac{10}{21} = \frac{11}{21} \] ### Step 5: Determine the outcomes based on the urns - If a prime number is rolled, a ball is chosen from urn A (which contains 2 white and 3 black balls). - If a non-prime number is rolled, a ball is chosen from urn B (which contains 3 white and 2 black balls). ### Step 6: Calculate the probability of drawing a white ball from each urn - From urn A, the probability of drawing a white ball is: \[ P(W | A) = \frac{2}{5} \] - From urn B, the probability of drawing a white ball is: \[ P(W | B) = \frac{3}{5} \] ### Step 7: Use Bayes' theorem to find \( P(B | W) \) We want to find the probability that the white ball drawn came from urn B, given that a white ball was drawn: \[ P(B | W) = \frac{P(W | B) \cdot P(B)}{P(W)} \] Where: - \( P(B) = P(\text{not prime}) = \frac{11}{21} \) - \( P(W) = P(W | A) \cdot P(A) + P(W | B) \cdot P(B) \) Calculating \( P(W) \): \[ P(W) = P(W | A) \cdot P(\text{prime}) + P(W | B) \cdot P(\text{not prime}) \] Substituting the values: \[ P(W) = \left(\frac{2}{5} \cdot \frac{10}{21}\right) + \left(\frac{3}{5} \cdot \frac{11}{21}\right) \] Calculating each term: \[ = \frac{20}{105} + \frac{33}{105} = \frac{53}{105} \] ### Step 8: Substitute back to find \( P(B | W) \) Now substituting back into Bayes' theorem: \[ P(B | W) = \frac{\left(\frac{3}{5}\right) \cdot \left(\frac{11}{21}\right)}{\frac{53}{105}} \] Calculating the numerator: \[ = \frac{33}{105} \] So, \[ P(B | W) = \frac{33/105}{53/105} = \frac{33}{53} \] ### Final Answer The probability that the white ball drawn is from urn B is: \[ \boxed{\frac{33}{53}} \]

To solve the problem step by step, we will use the concepts of probability and Bayes' theorem. ### Step 1: Determine the probabilities of rolling a die The probability of rolling a number on a die is directly proportional to that number. Therefore, we can express the probabilities as follows: - Let \( P(1) = k \) - Let \( P(2) = 2k \) - Let \( P(3) = 3k \) ...
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