Final answer:
To find the sale price of a $30 item with a 30% discount, first calculate the discount by multiplying 30% converted to a decimal (0.30) by the original price to get $9. Then, subtract this amount from the original price to find the sale price, which is $21.
Step-by-step explanation:
The question involves finding the sale price of an item after applying a discount, which is a common topic in mathematics, specifically in the area of percentages and financial arithmetic. To find the new price of a $30 item with a 30% discount, you first need to calculate the amount of the discount. Convert the percentage to a decimal by dividing by 100 (30% becomes 0.30), and then multiply this by the item's original price:
$30 × 0.30 = $9
Next, subtract the discount from the original price to find the new price:
$30 - $9 = $21
Thus, the sale price of the item after a 30% discount is $21.