An old asset is being evaluated in terms of its marginal cost. You are provided with the following information: $$ Investment Cost: $$40,000$ Annual Operating and Maintenance Cost: $$3,500$ in Year $1,$ increasing by $$1,800$ per year $$ Annual Cost for Risk of Breakdown: $$8,000$ per year $$ Useful Life: $6$ years $$ MARR $($Minimum Attractive Rate of Return$)$: $12\%$ Market Values: $$ Year $1$: $$25,000$ Year $2$: $$21,000$ Year $3$: $$17,000$ Year $4$: $$12,000$ Year $5$: $$7,000$ Year $6$: $$2,000$ Calculate the marginal cost of keeping this asset over its useful life.