Answer
$6250 in sales
Work Step by Step
Let s be the amount of sales. The amount of commission is 0.04s. Earnings is the total of the commission and the base salary of $200.
0.04s+200≥450⟶ subtract 200 from each side
0.04s+200−200≥450−200⟶ subtract
0.04s≥250⟶ divide each side by 0.04
0.04s÷0.04≥250÷0.04⟶ divide
s≥6250