By selling a book for Rs. 10, the publisher loses `(1/11)` of what it costs him. His cost price is -

Options

A. Rs. 9
B. Rs. 10
C. Rs. 11
D. Rs. 12

Answer

To find the cost price of the book, we can follow these steps:

### Step 1: Understand the Loss
The problem states that the publisher sells the book for Rs. 10 and incurs a loss of \( \frac{1}{11} \) of the cost price (CP).

### Step 2: Set Up the Equation
Let the cost price be \( CP \). The loss incurred is given by:
\[ \text{Loss} = \frac{1}{11} \times CP \]

### Step 3: Relate Selling Price (SP) to Cost Price (CP)
The selling price (SP) is given as Rs. 10. Since the publisher incurs a loss, we can express the relationship between SP, CP, and Loss:
\[ SP = CP - \text{Loss} \]
Substituting the loss from Step 2 into this equation gives:
\[ 10 = CP - \frac{1}{11} \times CP \]

### Step 4: Simplify the Equation
To simplify the equation, we can factor out \( CP \):
\[ 10 = CP \left(1 - \frac{1}{11}\right) \]
Calculating \( 1 - \frac{1}{11} \):
\[ 1 - \frac{1}{11} = \frac{11}{11} - \frac{1}{11} = \frac{10}{11} \]
Now the equation becomes:
\[ 10 = CP \times \frac{10}{11} \]

### Step 5: Solve for Cost Price (CP)
To find \( CP \), we can multiply both sides by \( \frac{11}{10} \):
\[ CP = 10 \times \frac{11}{10} = 11 \]

### Conclusion
Thus, the cost price of the book is Rs. 11.