If I would have purchased 11 articles for Rs. 10 and sold all the articles at the rate of 10 for Rs. 11, the profit per cent would have been:

Options

A. 0.1
B. 0.11
C. 0.21
D. 1

Answer

To solve the problem, we need to determine the profit percentage based on the given purchase and selling prices of the articles.

### Step-by-Step Solution:

1. **Calculate the Cost Price (CP) of One Article:**
- The total cost for 11 articles is Rs. 10.
- Therefore, the cost price of one article (CP) is:
\[ CP = \frac{10}{11} \text{ Rs.} \]

2. **Calculate the Selling Price (SP) of One Article:**
- The selling price for 10 articles is Rs. 11.
- Therefore, the selling price of one article (SP) is:
\[ SP = \frac{11}{10} \text{ Rs.} \]

3. **Calculate the Profit per Article:**
- Profit per article can be calculated as:
\[ \text{Profit} = SP - CP = \frac{11}{10} - \frac{10}{11} \]
- To subtract these fractions, we need a common denominator, which is 110:
\[ \text{Profit} = \frac{11 \times 11}{110} - \frac{10 \times 10}{110} = \frac{121 - 100}{110} = \frac{21}{110} \text{ Rs.} \]

4. **Calculate the Total Cost Price for 11 Articles:**
- The total cost price for 11 articles is Rs. 10.

5. **Calculate the Total Selling Price for 11 Articles:**
- The total selling price for 11 articles can be calculated as:
\[ \text{Total SP} = 11 \times SP = 11 \times \frac{11}{10} = \frac{121}{10} \text{ Rs.} \]

6. **Calculate the Total Profit for 11 Articles:**
- Total profit is the total selling price minus the total cost price:
\[ \text{Total Profit} = \text{Total SP} - \text{Total CP} = \frac{121}{10} - 10 = \frac{121}{10} - \frac{100}{10} = \frac{21}{10} \text{ Rs.} \]

7. **Calculate the Profit Percentage:**
- Profit percentage is calculated using the formula:
\[ \text{Profit Percentage} = \left( \frac{\text{Total Profit}}{\text{Total CP}} \right) \times 100 \]
- Substituting the values:
\[ \text{Profit Percentage} = \left( \frac{\frac{21}{10}}{10} \right) \times 100 = \left( \frac{21}{100} \right) \times 100 = 21\% \]

### Final Answer:
The profit percentage is **21%**.