the additional revenue the firm receives from selling the output produced from an additional unit of labor

Tri fecta, a partnership, had revenues of $369,000 in its first year of operations. the partnership has not collected on $45,000 of its sales and still owes $39,500 on $155,000 of merchandise it purchased. there was no inventory on hand at the end of the year. the partnership paid $27,000 in salaries. the partners invested $48,000 in the business and $23,000 was borrowed on a five-year note. the partnership paid $2,070 in interest that was the amount owed for the year and paid $9,500 for a two-year insurance policy on the first day of business. compute net income for the first year for tri fecta.