1. **State the problem:** We are given a principal amount $P = 25000$, interest earned $I = 5000$, and time $T = 4$ years. We need to find the rate of interest $R$. 2. **Formula used:** The simple interest formula is $$I = \frac{P \times R \times T}{100}$$ where $I$ is interest, $P$ is principal, $R$ is rate per annum, and $T$ is time in years. 3. **Substitute the known values:** $$5000 = \frac{25000 \times R \times 4}{100}$$ 4. **Simplify the equation:** Multiply both sides by 100 to clear the denominator: $$5000 \times 100 = 25000 \times R \times 4$$ $$500000 = 100000 \times R$$ 5. **Solve for $R$:** $$R = \frac{500000}{100000} = 5$$ 6. **Conclusion:** The rate of interest $R$ is 5%.