The probability that a student passes Physics test is 2/3 and the probability that he passes <strong>BOTH</strong> Physics test and English test is 11/15. The probability that he passes <strong>AT LEAST</strong> one test is 4/5. What is the probability that he passes English test?
- A. 11/15
- B. 13/15 ✓
- C. 14/15
- D. 1
Correct Answer: B. 13/15
Explanation
We are given P(P) = \frac{2}{3}, P(P \cap E) = \frac{11}{15}, and P(P \cup E) = \frac{4}{5}. Using the addition theorem, P(P \cup E) = P(P) + P(E) - P(P \cap E). Substituting the values: \frac{4}{5} = \frac{2}{3} + P(E) - \frac{11}{15}. Rearranging for P(E): P(E) = \frac{4}{5} - \frac{2}{3} + \frac{11}{15} = \frac{12 - 10 + 11}{15} = \frac{13}{15}.
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