A corporation makes industrlal batteries. Budgeted production was 6,000 batteries for the morith. The standard power cost is $890 per machine hour The company's standards indicate that each battery requires 61 machine hours Actual production was 6,400 batteries. Actual machine hours were 38,730 Actual power cost totaled $350.632 Deterinine the rate and efficlency variances for the variable overhead power cost