XYZ Corporation's customer service department is using ratio analysis to forecast their HR requirements. They know that the average customer service representative $($CSR$)$ can process $6$ customer calls per hour. They are expecting $5$ million customer calls in the coming year. The customer service center operates $5$ days a week, $8$ hours a day, no days taken for holidays. The company calculates an FTE at $40$ hours per week.

a$.$ How many FTEs will XYZ Corp. need to satisfy customer demand?

b$.$ XYZ assumes that customer calls will increase by $10\%$ next year. How many FTEs will XYZ need next year?

c$.$ The company uses a ratio approach to determine the number of supervisors they will employ, based on the number of CSRs$.$ XYZ uses a $7$:$1$ ratio of CSRs to supervisors. How