martha builds bookcases. the selling price of each is determined by the cost of each oak board and the cost of each mapleboard used to build the bookcase. martha finds the total cost of 4 oak boards and 12 oak boards and multiplies that cost by 1.5 to determine the selling price of each bookcase. the cost per oak board is always twice the cost of each maple board. enter an equation for the selling price, s, of each bookcase based on the cost of a single maple board, m.