Assume that the best cost driver that Sony has for variable factory overhead in the assembly department is machine hours. During April, the company budgeted 720,000 machine hours and $6,480,000 for its Texas plant’s assembly department. The actual variable overhead incurred was $6,870,000, which was related to 750,000 machine hours.

Required

a. Determine the variable overhead spending variance.

b. Determine the variable overhead efficiency variance.