Accounting help please

Stover Company uses the weighted-average method in its process costing system. Information concerning Department A for the month of June follows: All materials are added at the beginning of the process. The cost per equivalent unit for material costs is closest to: a. $0.83 b. $0.85 c. $0.97 d. $1.01 Sales minus variable expenses equals a. contribution margin b. fixed costs c. net sales d. gross margin In describing the cost equation, y = a + bx, "a" is: a. the dependent variable, cost b. the independent variable, the level of activity c. the total fixed costs d. the variable cost per unit of activity