A lаbоrаtоry perfоrms [а] billable procedures in a month. The charge per billable test is $[b], which includes all incurred expenses of $[c] per test plus a profit margin. What is the laboratory's total monthly profit margin from these billable procedures?Formula: Total Profit Margin = (Charge per test − Expense per test) × Number of tests(Round to the nearest whole dollar. Enter the number only — no $ or commas.)