1. **State the problem:** We are given the population of Africa in 2016 as 1.22 billion and in 2022 as 1,407,909,104. We need to: (i) Write the 2022 population in the form $a \times 10^n$ where $1 \leq a < 10$ and $n \in \mathbb{N}$. (ii) Calculate the percentage increase in population from 2016 to 2022, rounded to three significant figures. 2. **Part (i): Express 2022 population in scientific notation** The 2022 population is 1,407,909,104. To write in scientific notation, move the decimal point so that there is one digit before the decimal: $$1,407,909,104 = 1.407909104 \times 10^9$$ Rounding $a$ to three decimal places (optional for clarity): $$a = 1.41$$ So, $$\boxed{1.41 \times 10^9}$$ 3. **Part (ii): Calculate percentage increase** Formula for percentage increase: $$\text{Percentage increase} = \frac{\text{New value} - \text{Old value}}{\text{Old value}} \times 100$$ Substitute values: $$= \frac{1,407,909,104 - 1,220,000,000}{1,220,000,000} \times 100$$ Calculate numerator: $$= \frac{187,909,104}{1,220,000,000} \times 100$$ Simplify fraction: $$= \frac{\cancel{187,909,104}}{\cancel{1,220,000,000}} \times 100 \approx 0.154 \times 100$$ Calculate percentage: $$= 15.4\%$$ Rounded to three significant figures: $$\boxed{15.4\%}$$ **Final answers:** (i) $1.41 \times 10^9$ (ii) $15.4\%$