You invest in a piece of equipment costing $30,000. The equipment will be used for two years, at the end of which time the salvage value of the machine is expected to be $10,000. The machine will be used for 5,000 hours during the first year and 8,000 hours during the second year. The expected annual net savings in operating costs will be $25,000 during the first year and $40,000 during the second year. If your interest rate is 10%, what would be the equivalent net savings per machine-hour