18) Microcomputers are shipped to the University bookstore from three factories A, B, and C. You know that 2% of factory A's microcomputers have defects, whereas for Factory B it is 1%. Finally, If a computer is from Factory C. there is a 0.5% chance it will have a defect. The manager in the store receives a new shipment of microcomputers and discovers that 40% are from factory C. 40% are from factory B, and 20% are from factory A. a) Are the events "microcomputer comes from factory A" and "microcomputer comes from factory B" mutually exclusive? Explain