A machine purchased three years ago for $303,000 has a current book value using straight-line depreciation of $184,000; its operating expenses are $36,000 per year. A replacement machine would cost $239,000, have a useful life of nine years, and would require $12,000 per year in operating expenses. It has an expected salvage value of $76,000 after nine years. The current disposal value of the old machine is $88,000; if it is kept 9 more years, its residual value would be $15,000.Calculate the total costs in keeping the old machine and purchase a new machine.

David consumes two things: gasoline (g) and bread (b). david's utility function is u(g, b) = 10g^0.25 b^0.75. use the lagrange technique to solve for david's optimal choices of gasoline and bread as a function of the price of gasoline, p_g, the price of bread, p_b, and his income m. with recent decrease in the price of gasoline (maybe due to external shock such as shale gas production) does david increase his consumption of gasoline? for david, how does partial differential g/partial differential p_g depend on his income m? that is, how does david's change in gasoline consumption due to an increase in the price of gasoline depend on his income level? to answer these questions, find the cross-partial derivative, |partial differential^2 g/partial differential m partial differential p_g.