The first thing to notice is that this is an inequality. Since it says "at least" we know it's going to be greater than or equal to (>=). Her sales are what we are trying to find so we make that the unknown. We'll call it x.
325 + 4% of x >= 475
When you see "of" in an equation, replace it with (×).
325 + 4% × x >= 475
Convert % to decimal by dividing by 100 (move the decimal 2 places to the left).
325 + .08x >= 475
subtract 325 from each side.
.08x >= 475 - 325
.08x >= 150
Divide each side by .08
x >= 150 ÷ .08
x >= 1875
She has to make at least (greater than or equal to) $1,875 in sales.
