12. Sam the Plumber is deciding whether to replace of an old utility truck with a new one. Sam's old truck originally cost $30,000 and has $12,000 of accumulated depreciation. If Sam keeps the old truck, operating costs will be $7,000 per year for its remaining useful life of 6 years. If Sam replaces the old truck, he has a sales agent who can sell it for $22.000 less a 5% brokerage commission. A new truck will cost $31.000 and will have a useful life of 6 years. Annual operating costs for the new truck will be $5.000. Prepare a differential analysis that shows whether Sam should keep the old truck or replace it with a new truck