Step 1: Understanding the Concept:
In commercial transactions, the price printed on an item is called the marked price (or list price).
A discount is a price reduction offered to buyers, usually expressed as a percentage of this marked price.
The actual discount value is calculated by converting the discount percentage into a decimal or fraction and multiplying it by the marked price.
Key Formula or Approach:
The mathematical formula to find the discount value is:
\[ \text{Discount} = \text{Discount Percentage} \times \text{Marked Price} \]
To convert a percentage $P\%$ into a standard mathematical fraction, we divide by 100:
\[ P\% = \frac{P}{100} \]
Step 2: Detailed Explanation:
Let us use the values provided in the question:
- Marked Price $= Y$
- Discount Percentage $= A\%$
Convert the discount percentage $A\%$ into a mathematical fraction:
\[ A\% = \frac{A}{100} \]
Now, multiply this fraction by the marked price $Y$ to find the actual discount amount:
\[ \text{Discount} = \left(\frac{A}{100}\right) \times Y \]
This can be written in algebraic form as:
\[ \text{Discount} = \frac{A}{100} \times Y \]
This matches the expression in option (C).
Step 3: Final Answer:
The discount on a marked price $Y$ at a rate of $A\%$ is given by the expression $\frac{A}{100} \times Y$.
Therefore, the correct option is (C).