When should you use the "Reply All" function when replying to an email?

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?

The lee family is looking to buy a house in one of two suburban areas just outside of a major city, and air quality is a top priority for them. overall air quality is calculated by taking measures in 100 locations within each suburb and then calculating a measure of central tendency. in one suburb, there is a major bus station that creates very poor air quality at its location but has no impact in the surrounding parts of the suburb. in this situation, which measure of overall suburb air quality would be most useful?

What should a food worker use to retrieve ice from an ice machine?