# Ex 13.3, 11 - Chapter 13 Class 12 Probability

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Ex 13.3, 11 A manufacturer has three machine operators A, B and C. The first operator A produces 1% defective items, where as the other two operators B and C produce 5% and 7% defective items respectively. A is on the job for 50% of the time, B is on the job for 30% of the time and C is on the job for 20% of the time. A defective item is produced, what is the probability that it was produced by A? Let A : Event that item produced by operator A B : Event that item produced by operator B C : Event that item produced by operator C D : Event that item produced is defective We need to find out the Probability that item is produced by operator A if it is defective i.e. P(A|D) So, P(A|D) = . ( | ) . | + . | + . | Putting Values in the formula P(A|D) = . ( | ) . | + . | + . ( | ) = 0.5 0.01 0.5 0.01 + 0.3 0.05 + 0.2 0.07 = 0.005 0.005 + 0.015 + 0.014 = 0.005 0.034 = Therefore, required probability = 5 34

Chapter 13 Class 12 Probability

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Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.