The monthly sales of sunny electronics' new sound system are given by q(t) = 2,000t − 90t2 units per month, t months after its introduction. the price sunny charges is p(t) = 1,000 − t2 dollars per sound system, t months after introduction. find the rate of change of monthly sales.

Amachine purchased three years ago for $720,000 has a current book value using straight-line depreciation of $400,000: its operating expenses are $60,000 per year. a replacement machine would cost $480,000, have a useful life of nine years, and would require $26,000 per year in operating expenses. it has an expected salvage value of $130,000 after nine years. the current disposal value of the old machine is $170,000: if it is kept 9 more years, its residual value would be $20,000. calculate the total costs in keeping the old machine and purchase a new machine. should the old machine be replaced?

Demand increases by less than supply increases. as a result, (a) equilibrium price will decline and equilibrium quantity will rise. (b) both equilibrium price and quantity will decline. (c) both equilibrium price and quantity will rise

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