A wave soldering process is used in printed circuit boards. It is known that the error rate is 200 per million solders, where errors occur randomly and independently. A given board requires 5000 solders.
(a) What is the probability of 3 or more errors in a circuit board?
(b) Find the probability of a board having no solder errors.
(c) If a new design requires 2000 solders per board, what is the probability of an error-free board?
(d) The cost of rectification of a defective solder is $0.05, and the monthly production rate is 1 million boards. What is the expected cost reduction per month?