1. **State the problem:** We need to find a two-digit number whose digits sum to 12 and when reversed, the new number is \(\frac{4}{7}\) of the original number.
2. **Define variables:** Let the tens digit be \(x\) and the units digit be \(y\). The original number is \(10x + y\).
3. **Write equations from the problem:**
- Sum of digits: \(x + y = 12\)
- Reversed number: \(10y + x = \frac{4}{7}(10x + y)\)
4. **Express \(y\) from the first equation:**
\[ y = 12 - x \]
5. **Substitute \(y\) into the second equation:**
\[ 10(12 - x) + x = \frac{4}{7}(10x + 12 - x) \]
\[ 120 - 10x + x = \frac{4}{7}(9x + 12) \]
\[ 120 - 9x = \frac{4}{7}(9x + 12) \]
6. **Multiply both sides by 7 to clear the denominator:**
\[ 7(120 - 9x) = 4(9x + 12) \]
\[ 840 - 63x = 36x + 48 \]
7. **Bring all terms to one side:**
\[ 840 - 63x - 36x - 48 = 0 \]
\[ 792 - 99x = 0 \]
8. **Solve for \(x\):**
\[ 792 = 99x \]
\[ x = \frac{792}{99} \]
\[ x = 8 \]
9. **Find \(y\):**
\[ y = 12 - 8 = 4 \]
10. **Final answer:** The original number is \(10x + y = 10 \times 8 + 4 = 84\).
Two Digit Number 3047A8
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