Google LLC allocates its overhead costs to three main departments: Research & Development (R&D), Marketing, and Human Resources (HR). The total overhead costs for the period are $50,000,000. The allocation bases and usage for each department are as follows:

Department	Allocation Base	Usage
R&D	Number of Projects	50
Marketing	Advertising Expenditure	$10,000,000
HR	Number of Employees	1,000

Calculate the overhead allocation rate for each department and discuss how these rates reflect the utilization of resources in each department.