The completion of a construction job may be delayed due to strike. The probability of strike is 0.6. The probability that the construction job gets completed on time if there is no strike is 0.85 and the probability that the construction job gets completed on time if there is a strike is 0.35. What is the probability that the construction job will <strong>NOT</strong> be completed on time?

  1. A. 0.35
  2. B. 0.45
  3. C. 0.55
  4. D. 0.65

Correct Answer: B. 0.45

Explanation

Let S be a strike and C be timely completion. We are given P(S) = 0.6, P(S') = 0.4, P(C|S') = 0.85, and P(C|S) = 0.35. The probability of not completing on time is P(C') = P(C'|S)P(S) + P(C'|S')P(S') = (1 - 0.35)(0.6) + (1 - 0.85)(0.4) = 0.39 + 0.06 = 0.45.

Related questions on Statistics & Probability

Practice more NDA Mathematics questions