A microchip company has two machines that produce the chips. Machine I produces 55% of the chips, but 5% of its chips are defective. Machine II produces 45% of the chips and 15% of its chips are defective.
A) a chip is selected at random, find the probability that it is a defective chip.
B) A chip is selected at random and found to be defective. What is the probability that it came from machine I.