Ackermans Garage uses standards to plan and control labor time and expense. The standard time for an engine tune-up is 3.5 hours, and the standard labor rate is $15 per hour. Last week, 24 tune-ups were completed. The labor efficiency variance was 6 hours unfavorable, and the labor rate variance totaled $81 favorable. Required: a. Calculate the actual direct labor hourly rate paid for tune-up work last week