Cal's Carpentry is considering outsourcing its accounts receivable function. Currently, Cal employs two full-time clerks and one part-time clerk to manage accounts receivable. Total salary plus fringe cost is $102,960. Cal estimates that each account receivable incurs a $15 variable cost. The Small Business Accounts Receivables Group (SBARG) specializes in handling accounts receivable for small-tom medium size companies. Doris Roberts from SBARG has offered to do the accounts receivable for Cal's Carpentry at a fixed cost of $80,724 per year plus $20 per account receivable. Next year, Cal expects to have 2,768 accounts receivable. If the fixed annual cost offered by SBARG is nonnegotiable but it is willing to negotiate the variable cost, what variable cost from SBARG would make Cal indifferent to the two options