Final answer:
Charlie's starting salary was calculated by dividing his new salary, which includes a 9% pay rise, by 1.09. The starting salary was found to be approximately $2,600.
Step-by-step explanation:
Charlie received a 9% pay rise, which increased his salary to $2,834. To calculate his starting salary, we assume that his new salary is 109% of his original salary. We use the formula:
Starting Salary = Final Salary / (1 + Percentage Increase)
Starting Salary = $2,834 / 1.09
By performing the division, we find out that Charlie's starting salary was approximately $2,600.