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.
$0.04s+200\geq450\longrightarrow$ subtract 200 from each side
$0.04s+200-200\geq450-200\longrightarrow$ subtract
$0.04s\geq250\longrightarrow$ divide each side by 0.04
$0.04s\div0.04\geq250\div0.04\longrightarrow$ divide
$s\geq6250$
