$5\mathrm{.}8$Use Method $1($combined depreciation and investment costs for ownership costs$)$ to determine the probable cost per hour of owning and operating a rubber tire unit of equipment with a $250-$hp diesel engine. The following conditions apply.Factory delivered price $$450,000$ Sales tax $5\%$ of delivered price Unloading and assembling $$2,500$ Salvage value $$120,000$Useful life $5$ yr Hours used per year $1,500$ hr Interest on investment $8\%$ Maintenance and repairs $70\%$ of straight$-$line depreciation Diesel engine $250$ hp Operating factor $0\mathrm{.}60$ Fuel costs $$4\mathrm{.}00/$gal Crankcase capacity $8$ gal Hours between oil changes $120$ hr Oil costs $$16/$ga