Answer:
The original selling price of the swimsuits is b) $72.71.
Explanation:
Let "x" be the original price of the swimsuits.
According to the problem statement, the markdown is 45%, which means that the swimsuits are sold at 55% of the original price:
55% of x = $39.99
To solve for "x", we need to isolate it on one side of the equation. We can start by dividing both sides by 55% (or 0.55):
x = $39.99 ÷ 0.55
x = $72.71
Therefore, the original selling price of the swimsuits was $72.71. Option b is the correct answer.