Quality control
Suppose a box contains 3 defective transistors and 12 good transistors. If 2 transistors are drawn from the box without replacement, what is the probability that
(a) the first transistor is good and the second transistor is defective?
(b) the first transistor is defective and the second one is good?
(c) one of the transistors drawn is good and one of them is defective?
