[solved]probability question 1. The problem statement, all variables and given/known data Three machines A, B, and C produce 50%, 30% and 20% respectively of the total number of items at a factory. Each produces a number of defective: 3%, 4% and 5% respectively. (a) If an item produced by one of these machines is selected, find the probability that it is defective. (b) Now suppose that a manufactured item is selected at random and is found to be defective. Find the probability that this item was produced by machine A. 2. Relevant equations N/A 3. The attempt at a solution is part (a) Pr = (3%+4%+5%)/(50%*30%*20%)? and no idea on part b thanks a lot!