The question you provided is in Bengali. Here’s the translation and breakdown of the problem:

Translation:

A shopkeeper sold 100 pencils and incurred a loss equivalent to the selling price of 20 pencils. What is the percentage of loss?

Options:

• (A) 25%
• (B) 20%
• (C) 15%
• (D) 12%

Solution:

Let’s assume the cost price of one pencil is $C$, and the shopkeeper sells 100 pencils.

1. Cost price of 100 pencils:
   Total cost price $= 100 \times C = 100C$

2. Selling price of 100 pencils:
   The shopkeeper incurred a loss equivalent to the selling price of 20 pencils, which means he sold 100 pencils at the price of 80 pencils.
   Total selling price $= 80 \times C = 80C$

3. Loss incurred:
   Loss = Cost price - Selling price
   $\text{Loss} = 100C - 80C = 20C$

4. Loss percentage:
   Loss percentage $= \left( \frac{\text{Loss}}{\text{Cost Price}} \right) \times 100$
   $\text{Loss percentage} = \left( \frac{20C}{100C} \right) \times 100 = 20\%$

Correct Answer:

The loss percentage is 20%.
Thus, the correct option is (B).

Would you like further details or have any questions?

Here are 5 related questions:

1. If the shopkeeper had sold 100 pencils for the price of 90 pencils, what would the loss percentage be?
2. How would the profit percentage be calculated if the shopkeeper gained an equivalent of 10 pencils’ price?
3. What would the selling price be if the shopkeeper wanted to avoid any loss?
4. How is the percentage formula for profit different from that of loss?
5. If the shopkeeper sold the pencils for the price of 110 pencils, what would the profit percentage be?

Tip: In percentage-based problems, always compare the loss or profit with the original cost price to avoid confusion.