A bookseller sells a book for Rs.100, gaining Rs. 20. His gain per cent is

Options

A. 2
B. 25
C. 0.22
D. none of these

Answer

To find the gain percentage of the bookseller, we can follow these steps:

### Step 1: Identify the Selling Price (SP) and Gain
The selling price of the book is given as Rs. 100, and the gain is given as Rs. 20.

### Step 2: Calculate the Cost Price (CP)
To find the cost price, we use the formula:
\[ \text{Cost Price (CP)} = \text{Selling Price (SP)} - \text{Gain} \]

Substituting the values:
\[ \text{CP} = 100 - 20 = 80 \]

### Step 3: Calculate the Gain Percentage
The formula for gain percentage is:
\[ \text{Gain Percentage} = \left( \frac{\text{Gain}}{\text{Cost Price (CP)}} \right) \times 100 \]

Substituting the values:
\[ \text{Gain Percentage} = \left( \frac{20}{80} \right) \times 100 \]

### Step 4: Simplify the Calculation
\[ \text{Gain Percentage} = \left( 0.25 \right) \times 100 = 25\% \]

### Final Answer
The gain percentage is **25%**.

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