Solve by using excel:

6.8 Eight years ago, Ohio Valley Trucking purchased a large-capacity dump truck for $115,000 to provide short-haul earthmoving services. The company sold it today for $45,000. Operating and mainte- nance costs averaged $10,500 per year. A complete overhaul at the end of year 4 cost an extra $3600 Calculate the annual cost of the truck at 8% per year interest. 6.17 Aremotely located air sampling station can be pow ered by solar cells or by running an above ground electric line to the site and using conventional power. Solar cells will cost $16,600 to install and will have a useful life of 5 years with no salvage value. Annual costs for inspection, cleaning, etc are expected to be $2400. A new power line will cost $31,000 to install, with power costs expected to be $1000 per year. Since the air sampling project will end in 5 years, the salvage value of the line is considered to be zero. At an interest rate of 10% per year, (a) which alternative should be selected on the basis of an annual worth analysis and (b) what must be the first cost of the above ground line to make the two alternatives equally attractive economically? 7.9 Determine the rate of return for the cash flows shown in the diagram. (If requested by your instructor, show both hand and spreadsheet solutions.) $7000 0 3 4 7 8 Year $90 $90 $90 $200 $200 $200 $3000