Twice the difference between two numbers is equal to their sum .If one number is 15, find the other number
A. 15
B. 10
C. 5
D. 20

Options

A. B
B. A
C. C
D. D

Answer

To solve the problem, we need to set up an equation based on the information given in the question.

### Step-by-Step Solution:

1. **Identify the Known Values**:
- One number is given as 15.
- Let the other number be represented as \( X \).

2. **Write the Expressions for Difference and Sum**:
- The difference between the two numbers is \( 15 - X \).
- The sum of the two numbers is \( 15 + X \).

3. **Set Up the Equation**:
- According to the problem, twice the difference is equal to the sum. Therefore, we can write the equation:
\[ 2(15 - X) = 15 + X \]

4. **Expand and Simplify the Equation**:
- Expanding the left side gives:
\[ 30 - 2X = 15 + X \]

5. **Rearrange the Equation**:
- Move all terms involving \( X \) to one side and constant terms to the other side:
\[ 30 - 15 = 2X + X \]
- This simplifies to:
\[ 15 = 3X \]

6. **Solve for \( X \)**:
- Divide both sides by 3:
\[ X = \frac{15}{3} = 5 \]

7. **Conclusion**:
- The other number is \( 5 \).

### Final Answer:
The other number is \( 5 \) (Option C).

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