Consider two events E1 and E2 such that P(E1) = 1/2, P(E2) = 1/3, and P(E1 intersect E2) = 1/5. Which of the following statements is/are true? A. P(E1 union E2) = 19/30 B. Events E1 and E2 are independent C. Events E1 and E2 are not independent D. P(E1 | E2) = 4/5

GATE 1999 · Engineering Mathematics · Independent Events · medium

Answer: C. Events E1 and E2 are not independent

  1. Independence check: 1/6 != 1/5, so E1 and E2 are NOT independent. Option C is true; B is false.
  2. Check option A: P(E1 union E2): P(E1 union E2) = 1/2 + 1/3 - 1/5 = 15/30 + 10/30 - 6/30 = 19/30.
  3. Check option D: P(E1 | E2): P(E1 | E2) = (1/5) / (1/3) = 3/5, not 4/5. Option D is false.