the original price is $28.57
If the discount is 30% then the amount paid is 70% of the original price. Sally paid $20, it is the discounted price, equivalent to 70%.
We need to divide $20 by 70% to get the original price or the 100%.
$20 / 70% = $28.57 original price.
Since the handbag was has discount of 30%, we multiply the original price with the 30% to get the discount value.
$28.57 * 30% = $8.57 discount
To check: deduct the discount from the original price to get the discounted price.
$28.57 - $8.57 = $20 discounted price. price paid by Sally
