#### Explanation:

To determine the amount of discount ($d$) offered by the store, we calculate 15% of the sale price. Thus:

$d = 300 \times \frac{15}{100}$

$d = 3 \cancel{00} \times \frac{15}{1 \cancel{00}}$

$d = 3 \times 15$

$d = 45$

If the amount of discount is known, the sale price ($s$) of the item will be the regular price minus the discount. Hence:

$s = 300 - 45$

$s = 255$