1. **State the problem:** We want to estimate the number of chickens on a farm after 15 years, given an initial population of 20,000 and an annual increase of 3.6% using simple interest. 2. **Formula used:** Simple interest growth can be modeled as $$A = P(1 + rt)$$ where: - $A$ is the amount after time $t$ - $P$ is the principal or initial amount - $r$ is the rate of increase per year (in decimal form) - $t$ is the time in years 3. **Convert the percentage rate to decimal:** $$r = 3.6\% = 0.036$$ 4. **Plug in the values:** $$P = 20000, \quad r = 0.036, \quad t = 15$$ 5. **Calculate:** $$A = 20000(1 + 0.036 \times 15) = 20000(1 + 0.54) = 20000 \times 1.54 = 30800$$ 6. **Interpretation:** After 15 years, the estimated number of chickens on the farm is **30,800**.