CBSE Class 12 Mathematics Probability Q #691
COMPETENCY BASED
APPLY
1 Marks 2025 AISSCE(Board Exam) MCQ SINGLE
If \(P(A)=\frac{1}{7}\), \(P(B)=\frac{5}{7}\) and \(P(A\cap B)=\frac{4}{7},\) then \(P(\overline{A}|B)\) is:
(A) \(\frac{6}{7}\)
(B) \(\frac{3}{4}\)
(C) \(\frac{4}{5}\)
(D) \(\frac{1}{5}\)
Correct Answer: D
Explanation
ok

AI Tutor Explanation

Powered by Gemini

Step-by-Step Solution

We are given \(P(A) = \frac{1}{7}\), \(P(B) = \frac{5}{7}\), and \(P(A \cap B) = \frac{4}{7}\). We need to find \(P(\overline{A}|B)\).

By definition of conditional probability, \(P(\overline{A}|B) = \frac{P(\overline{A} \cap B)}{P(B)}\).

We know that \(P(B) = P(A \cap B) + P(\overline{A} \cap B)\). Therefore, \(P(\overline{A} \cap B) = P(B) - P(A \cap B)\).

Substituting the given values, we have \(P(\overline{A} \cap B) = \frac{5}{7} - \frac{4}{7} = \frac{1}{7}\).

Now, we can find \(P(\overline{A}|B) = \frac{P(\overline{A} \cap B)}{P(B)} = \frac{\frac{1}{7}}{\frac{5}{7}} = \frac{1}{5}\).

Correct Answer: \(\frac{1}{5}\)

AI Suggestion: Option D

AI generated content. Review strictly for academic accuracy.

Pedagogical Audit
Bloom's Analysis: This is an APPLY question because it requires the student to apply the formula for conditional probability and the complement of an event to solve the problem.
Knowledge Dimension: PROCEDURAL
Justification: The question requires the student to follow a specific procedure to calculate the conditional probability, involving the use of formulas and algebraic manipulation.
Syllabus Audit: In the context of CBSE Class 12, this is classified as COMPETENCY. The question assesses the student's ability to apply the concepts of probability and conditional probability in a problem-solving context, rather than simply recalling definitions or theorems.

More from this Chapter

SA
A survey was conducted on the patients who have undergone knee replacement surgeries. It was found that, Robotic Knee replacement surgeries have 90% success rate. On a particular day, robotic surgery was performed on three patients, A, B and C, one after the other. Assuming that the success and failure of each surgery is independent of each other, find the probability that: (i) exactly one surgery is successful, (ii) at most two surgeries are successful.
SA
A person has a fruit box that contains 6 apples and 4 oranges. He picks out a fruit three times, one after the other, after replacing the previous one in the box. Find: (i) The probability distribution of the number of oranges he draws. (ii) The expectation of the random variable (number of oranges).
MCQ_SINGLE
For two events A and B such that $P(A) \ne 0$ and $P(B) \ne 1$, $P(A^{\prime}/B^{\prime})=$
LA
(a) In answering a question on a multiple choice test, a student either knows the answer or guesses. Let 3/5 be the probability that he knows the answer and 2/5 be the probability that he guesses. Assuming that a student who guesses at the answer will be correct with probability 1/3. What is the probability that the student knows the answer, given that he answered it correctly? OR (b) A box contains 10 tickets, 2 of which carry a prize of ₹8 each, 5 of which carry a prize of ₹4 each, and remaining 3 carry a prize of ₹2 each. If one ticket is drawn at random, find the mean value of the prize.
SA
A pair of dice is thrown simultaneously. If X denotes the absolute difference of the numbers appearing on top of the dice, then find the probability distribution of X.
View All Questions