Please help with explaination.

Exercise 1 Oro Company has two departments with the following production data. It has historically used a single-plant-wide overhead rate based on direct labor cost. Welding Fabrication Manufacturing overhead costs $ 160,000 $ 240,000 Direct labor cost 40,000 $ 10,000 Direct labor hours 4,000 1,000 Machine hours 100 2,000 a) Single Plant-Wide Overhead Rate Compute departmental overhead rates. Assume welding applies overhead using direct labor hours and fabrication using machine hours. b) Departmental Overhead Rate - Welding per DL hr c) Departmental Overhead Rate - Fabrication per mach. Hr