Let events that production is done by machine A is E1, the production done by machine B is E2, the production done by machine C is E3. The event that product being defective is E The probabilities are P(E1)=
20
100
,P(E2)=
30
100
,P(E3)=
50
100
Probability, Machine A has defective production P(
E
E1
)=
5
100
Machine B has defective production P(
E
E2
)=
3
100
Machine C has defective production P(
E
E3
)=
2
100
An item being selected and found defective, then the probability that it is produced by machine B is