A bolt is drawn at random from the product and is found
to be defective What is the probability that it is manufactured by the machine B Solution Let events B1, B2, B3 be the following :
B1 : the bolt is manufactured by machine A
B2 : the bolt is manufactured by machine B
B3 : the bolt is manufactured by machine C
Clearly, B1, B2, B3 are mutually exclusive and exhaustive events and hence, they
represent a partition of the sample space Let the event E be ‘the bolt is defective’