Assertion : If marked price of an article is 1300 and discount is 10%. The selling price of the article is 1180.
Reason : The selling price of an article can be calculated by the formula S.P. = Marked price - Discount.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Answer

To solve the problem, we need to verify both the assertion and the reason provided in the question step by step.

### Step 1: Understand the Assertion
The assertion states that if the marked price of an article is Rs. 1300 and the discount is 10%, then the selling price of the article is Rs. 1180.

### Step 2: Calculate the Discount
To find the selling price, we first need to calculate the discount. The discount is calculated as follows:
\[ \text{Discount} = \text{Marked Price} \times \left(\frac{\text{Discount Percentage}}{100}\right) \]
Substituting the values:
\[ \text{Discount} = 1300 \times \left(\frac{10}{100}\right) = 1300 \times 0.10 = 130 \]

### Step 3: Calculate the Selling Price
Now, we can calculate the selling price using the formula:
\[ \text{Selling Price} = \text{Marked Price} - \text{Discount} \]
Substituting the values:
\[ \text{Selling Price} = 1300 - 130 = 1170 \]

### Step 4: Compare the Selling Price with the Assertion
According to our calculation, the selling price is Rs. 1170, but the assertion states that the selling price is Rs. 1180. Therefore, the assertion is incorrect.

### Step 5: Verify the Reason
The reason states that the selling price of an article can be calculated by the formula:
\[ \text{Selling Price} = \text{Marked Price} - \text{Discount} \]
We have used this formula in our calculation, and it is indeed correct.

### Conclusion
- **Assertion**: Incorrect (Selling Price is Rs. 1170, not Rs. 1180)
- **Reason**: Correct (The formula for selling price is valid)