Sally can clean the house in 6 hours, her father can clean the house in 4 hours, and her younger brother, dennis, can completely mess up the house in 10 hours. if sally and her father clean and dennis plays, how long will it take to clean the house?

Quick computing currently sells 12 million computer chips each year at a price of $19 per chip. it is about to introduce a new chip, and it forecasts annual sales of 22 million of these improved chips at a price of $24 each. however, demand for the old chip will decrease, and sales of the old chip are expected to fall to 6 million per year. the old chips cost $10 each to manufacture, and the new ones will cost $14 each. what is the proper cash flow to use to evaluate the present value of the introduction of the new chip? (enter your answer in millions.)