I have a hard time with this guys. Two machines $A$ and $B$ respectively produce 30% and 70% of materials for a company, while respectively 3% and 5% of the produced units are defective.
a) What is probability that one material out of the entire output is defective
b) probability that that defective material was produced by machine A
c) probability that that defective material was produced by machine B
I let the total output be equal to 100 units, the machine A producing 30 units and machine B producing 70 units.