Final answer:
The correct equation to represent an employee's monthly income (I) at a sales firm, considering a $2,000 fixed salary and an 18% commission on total sales (T), is I = 2000 + 0.18T.
Step-by-step explanation:
An employee's monthly income (I) in a sales firm is composed of a fixed salary and a commission that is a percentage of the employee's total sales during the month (T). The fixed salary is $2,000 per month, and the commission is 18% of total sales. Thus, the monthly income can be calculated with the formula I = 2000 + 0.18T, where T is the total sales.
To calculate the commission, you multiply the total sales by 0.18 (or 18%). You then add the fixed salary of $2000 to the commission amount to get the total income. Therefore, the correct equation that represents an employee's monthly income is I = 2000 + 0.18T.