Please provide clear solutions and formulas and equations to solve. I am trying to build an excel spreadsheet to help solve questions like this so if you could answer in a way I can plug into excel that would be great. Thank you.

Test Company produces two products from a common input: Product A and Product B. One batch of the common input yields 500 units of Product A and 100 units of Product B. The joint costs for one batch are $25,000. Product A can be sold at the split-off point for $60 per unit. Product B can be sold at the split-off point for $200 per unit. Alternatively, Product B can be processed into 80 units of Product C that will sell for $300 per unit. Additional process costs for one batch of Product C will be $3,500.

Determine the increase (decrease) in income if Product B is processed further into Product C.