PROBLEM $1$

The manager of a construction project must decide between two different machines. Machine A will have an initial cost of $$42,000,$ an annual operating cost of $$28,000,$ and a service life of $4$ years. Machine B will cost $$51,000$ to buy and will have an annual operating cost of $$17,000$ during its $4-$year life. At an interest rate of $10\%$ per year, which should be selected based on a present worth analysis?