Selected information from the lowa Instruments accounting records for April follows: Additional information for April follows: The labor wage rate was $30 per hour. During the month, sales revenue was $320,000, and selling and administrative costs were $73,000. This company has no indirect materials or supplies. The company applies manufacturing overhead on the basis of direct labor-hours. Customer returns are discarded and not resold. Required: a. What was the cost of direct materials purchased in April? b. What was the over- or underapplied manufacturing overhead for April? c. What was the manufacturing overhead application rate in April? d. What was the cost of products completed during April? e. What was the balance of the Work-in-Process Inventory accou