Step-by-step explanation:
Consider the problem
Let, E 1 and E 2
be the respective events of items produced by machine A and B.
And let x be the event that the produced item was found to be defective.
Therefore,
Probability of items produced by machine A,P (E 1)=60%= 53
Probability of items produced by machine B,P (E 2)=40%= 52
And,
Probability that machine A produced defective items, P( E 1 x)=2%= 1002
Probability that machine B produced defective items, P( E 2 x)=1%= 1001
So, the probability that randomly selected items was from machine A is given by P( x E 1)
Now, Apply Bayes' Theorem
P( x E 1)= P(E 1)P( E 1x )+P(E 2)P( E 2x)P(E 1)P( E 1x)= 52× 1001 + 5
3× 1002
53× 100
2= 2+5
6= 11
6
Hence, the required probability of machine A is
11
6