Final answer:
The sale price of the $300 suit after a 30% markdown is calculated by finding the discount amount ($90) and subtracting it from the original price, resulting in a sale price of $210.
Step-by-step explanation:
To find the sale price of the suit, we first need to calculate the amount of the discount. Since the suit is marked down by 30%, we multiply the original price of the suit ($300) by 30% (or 0.30) to find the discount amount.
$300 × 0.30 = $90
Now, we subtract the discount amount from the original price to find the sale price of the suit:
$300 - $90 = $210
Therefore, the sale price of the $300 suit after a 30% mark down is $210.