Please answer without the use of excel, and give a step by step solution. Thanks

A contractor estimates maintenance costs for a new backhoe to be $275 for the first month with a monthly increase of 0.5%. The contractor can buy a 4-year maintenance contract for $13,000 at any point. If the contract is purchased at the same time as the backhoe is purchased, the dealer has offered,t% discount. At an interest rate of 0.75% per month, what should the contractor do?(Why? (25 points) hat should the contractor do?Why2 (25 points)