1. The problem is to simplify the fraction $\frac{15}{25}$. 2. To simplify a fraction, we divide the numerator and denominator by their greatest common divisor (GCD). 3. Find the GCD of 15 and 25. The factors of 15 are 1, 3, 5, 15. The factors of 25 are 1, 5, 25. The greatest common factor is 5. 4. Divide numerator and denominator by 5: $$\frac{15 \div 5}{25 \div 5} = \frac{3}{5}$$ 5. So, the simplified form of $\frac{15}{25}$ is $\frac{3}{5}$.