Example 15
Last updated at Dec. 8, 2016 by Teachoo
Transcript
Example 15 (Method 1) A person has undertaken a construction job. The probabilities are 0.65 that there will be strike, 0.80 that the construction job will be completed on time if there is no strike, and 0.32 that the construction job will be completed on time if there is a strike. Determine the probability that the construction job will be completed on time Let A : Construction job completed on time B: There will be strike P(there will be strike) = 0. 65 P(B) = 0. 65 P(no strike) = P(B’) = 1 – P(B) = 1 – 0.65 = 0.35 So, P(B’) = 0.35 Probability that the construction job is completed on time = Probability that there will be a strike × Probability that the job is completed on time + Probability that there will not be a strike × Probability that the job is completed on time P(A) = P(B) . P(A|B) + P(B’) . P(A|B’) P(construction job is completed if no strike) = 0.80 P(A|B’) = 0.80 P(construction job is completed if no strike) = 0.32 P(A|B) = 0.32 Now, P(A) = P(B) P(A|B) + P(B’) . P(A|B’) = 0.65 × 0.32 + 0.35 × 0.80 = 0.208 + 0.28 = 0.488 Thus, required probability is 0.488 Example 15 (Method 2) A person has undertaken a construction job. The probabilities are 0.65 that there will be strike, 0.80 that the construction job will be completed on time if there is no strike, and 0.32 that the construction job will be completed on time if there is a strike. Determine the probability that the construction job will be completed on time Probability that the construction job is completed on time = Probability that there will be a strike × Probability that the job is completed on time + Probability that there will not be a strike × Probability that the job is completed on time Probability that there will not be a strike = 1 – Probability of strike = 1 – 0.65 = 0.35 Now, Probability that the construction job is completed on time = Probability that there will be a strike × Probability that the job is completed on time + Probability that there will not be a strike × Probability that the job is completed on time = 0.65 × 0.32 + 0.35 × 0.80 = 0.208 + 0.28 = 0.488 Thus, required probability is 0.488
Examples
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Example 15 You are here
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Example 18 Important
Example 19
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Example 21 Important
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Example 25 Important
Example 26 Important
Example 27 Important
Example 28 Important
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Example 31 Important
Example 32 Important
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Example 35 Important
Example 36 Important
Example 37
Chapter 13 Class 12 Probability
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About the Author
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 8 years. He provides courses for Practical Accounts, Taxation and Efiling at teachoo.com .