Final answer:
The average annual salary for the four employees is calculated by summing up their salaries and dividing by the number of employees, which results in $47,500.
Step-by-step explanation:
The student asked about the average (mean) annual salary of four employees with salaries of $55,000, $50,000, $40,000, and $45,000. To determine the average salary, we add together the salaries of all four employees and then divide by the number of employees. The formula for finding an average is:
Average Salary = (Sum of all salaries) / (Number of employees)
Plugging in the values we have:
Average Salary = ($55,000 + $50,000 + $40,000 + $45,000) / 4
Average Salary = $190,000 / 4
Average Salary = $47,500
Therefore, the average annual salary for these four employees is $47,500, which corresponds to option (a).