White Tiger Electronics produces CD players using an automated assembly line process. The standard cost of CD players is $$150$ per unit $($labor$,$ $$30$; materials, $$0$; and overhead, $$50).$ The sales price is $$300$ 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?