In a certain code language,
`12 xx 7 = 408`
`9 xx 8 = 207`
`13 xx 7 = ?`
What will replace the '?' mark sign.

Options

A. 190
B. 910
C. 901
D. 109

Answer

To solve the problem, we need to decode the pattern used in the given equations. Let's break it down step by step.

### Step 1: Understand the given equations
We have two equations in a code language:
1. \( 12 \times 7 = 408 \)
2. \( 9 \times 8 = 207 \)

### Step 2: Calculate the actual multiplication
Let's calculate the actual products:
- For the first equation:
\[ 12 \times 7 = 84 \]
- For the second equation:
\[ 9 \times 8 = 72 \]

### Step 3: Analyze the code representation
Now, we need to see how the products (84 and 72) relate to the coded numbers (408 and 207):
- For \( 84 \):
- Reverse the digits: \( 84 \) becomes \( 48 \)
- Add a zero in between: \( 48 \) becomes \( 408 \)

- For \( 72 \):
- Reverse the digits: \( 72 \) becomes \( 27 \)
- Add a zero in between: \( 27 \) becomes \( 207 \)

### Step 4: Apply the same logic to the new equation
Now, we need to find the code for \( 13 \times 7 \):
- First, calculate the product:
\[ 13 \times 7 = 91 \]

### Step 5: Reverse the digits and add zero
- Reverse the digits of \( 91 \): it becomes \( 19 \)
- Add a zero in between: \( 19 \) becomes \( 109 \)

### Conclusion
Thus, the answer to \( 13 \times 7 \) in the code language is:
\[ \boxed{109} \]