On April 9, 2024, Banks Corp., a calendar year-end company, purchased materials costing $300,000 for use in various future R&D activities. The "R&D Materials Inventory" account was debited at the time of this purchase. As of December 31, 2024, materials costing $75,000 remain unused. There was a beginning balance in the R&D Materials Inventory account of $40,000. Required: Prepare the year-end adjusting entry related to the R&D Materials Inventory