Jackson Grills Has Supplied the Following Information from Its Accounting

Jackson Grills has supplied the following information from its accounting records for the month of August.
Required: Solve for the missing amounts (?).
$$\begin{array} { l r } \text { Direct labour cost } & \$ 11,500 \\\text { Purchases of raw materials } & 20,000 \\\text { Factory depreciation } & 7,500 \\\text { Advertising } & 10,000 \\\text { Factory property taxes } & 6,500 \\\text { Materials inventory, } 8 / 1 & 1,250 \\\text { Materials inventory, } 8 / 31 & 2,500 \\\text { Work-in-process inventory, } 8 / 1 & ? \\\text { Work-in-process inventory, } 8 / 31 & 1,500 \\\text { Cost of goods manufactured } & 45,850 \\\text { Sales revenue } & ? \\\text { Executive salary cost } & 25,000 \\\text { Finished goods inventory, } 8 / 1 & 5,500 \\\text { Finished goods inventory, } 8 / 31 & 4,250 \\\text { Operating income } & 67,900 \\\text { Gross margin } & ?\end{array}$$