Respuesta :
Answer:
0.4762 = 47.62% probability that this bulb was produced by factory A
Step-by-step explanation:
Conditional Probability
We use the conditional probability formula to solve this question. It is
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]
In which
P(B|A) is the probability of event B happening, given that A happened.
[tex]P(A \cap B)[/tex] is the probability of both A and B happening.
P(A) is the probability of A happening.
In this question:
Event A: Bulb is defective.
Event B: Produced by factory A.
Probability of a bulb being defective.
5% of 40%(factory A)
3% of 20%(factory B)
4% of 40%(factory C). So
[tex]P(A) = 0.05*0.4 + 0.03*0.2 + 0.04*0.4 = 0.042[/tex]
Defective and from factory A:
5% of 40%. So
[tex]P(A \cap B) = 0.05*0.4 = 0.02[/tex]
What is the probability that this bulb was produced by factory A?
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.02}{0.042} = 0.4762[/tex]
0.4762 = 47.62% probability that this bulb was produced by factory A
