I Cant seem to find the right answer for part C.

White Tiger Electronics produces CD players using an automated assembly line process. The standard cost of CD players is $144 per unit (labor, $28; materials, $67; and overhead, $49). The sales price is $275 per unit. a. To achieve a 15 percent multifactor productivity improvement by reducing materials costs only, one needs to reduce the materials cost by 28.36 percent. (Enter your response as a percent rounded to two decimal places.) b. To achieve a 15 percent multifactor productivity improvement by reducing labor costs only, one needs to reduce the labor cost by 67.08 percent. (Enter your response as a percent rounded to two decimal places.) c. To achieve a 15 percent multifactor productivity improvement by reducing overhead costs only, one needs to reduce the overhead cost by 26.63 percent. (Enter your response as a percent rounded to two decimal places.)