ELGI Electronics produces speakers using an automated assembly process. The standard cost of the speakers is $225 per unit (labor, $45; materials, $105; and overhead, $75). The sales price of the speakers is $400 per unit. a) To achieve a 10 percent multifactor productivity improvement by reducing materials costs only, by what percentage must these costs be reduced? b) To achieve a 10 percent multifactor productivity improvement by reducing labor costs only, by what percentage must these costs be reduced? c) To achieve a 10 percent multifactor productivity improvement by reducing overhead costs only, by what percentage must these costs be reduced?