Answer: Therefore, the commission rate is 18%.
Step-by-step explanation: To find the commission rate, we divide the commission earned by the total sales and then express it as a percentage.
Commission Rate = (Commission Earned / Total Sales) * 100
In this case, the commission earned is $540 and the total sales are $3000. Plugging these values into the formula, we have:
Commission Rate = (540 / 3000) * 100
Calculating this expression, we get:
Commission Rate = 0.18 * 100