how do i work this problem out please do it in simple terms

Riverside, Inc., wants to update the finish on its window frame. It has two choices: (a) buy new equipment at a cost of 20000; (b) make major modifications at a cost of $13,000. If the firm chooses to buy new equipment, materials and labor will be $3 per frame. If it chooses to make modifications, materials and labor will be $5 per frame. If the company thinks it can sell 3600 units at a selling price of $60, which of the following option is better? (b) make major modifications None of these O It does not matter which option is chosen. Correct An : swer: (a) purchase new equipment (a) purchase new equipment Sell 700 units after (a) purchasing new equipment and sell 2900 units after (b) making major modifications