1. **Problem statement:** We need to find how many maize plants can be planted in one acre if the spacing is 75 cm between rows and 30 cm between plants in a row. 2. **Formula and explanation:** The number of plants per unit area is given by dividing the total area by the area occupied by each plant. 3. **Convert units:** - 1 acre = 4046.86 square meters - Spacing between rows = 75 cm = 0.75 m - Spacing between plants = 30 cm = 0.30 m 4. **Calculate area per plant:** $$\text{Area per plant} = 0.75 \times 0.30 = 0.225 \text{ m}^2$$ 5. **Calculate number of plants:** $$\text{Number of plants} = \frac{4046.86}{0.225} \approx 17986.05$$ 6. **Interpretation:** Approximately 17986 maize plants can be planted in one acre with the given spacing.