The table shows the population and area of three countries in 2020.
(a) Calculate the difference in population between Nigeria and Vietnam.
(b) Which of Comoros or Vietnam has the greater population density? Show your working.
[Population density = \(\frac{population}{area(km^{2})}\)]
▶️ Answer/Explanation
Ans (a): 1.087 × 10⁸ or 108,700,000
Difference = Nigeria population (2.06×10⁸) – Vietnam population (9.73×10⁷) = 1.087×10⁸
Ans (b): Comoros
Comoros density = 8.70×10⁵ ÷ 1.86×10³ ≈ 468/km²
Vietnam density = 9.73×10⁷ ÷ 3.10×10⁵ ≈ 314/km²
Comoros has higher population density.
(a) Write 0.00273 in standard form.
(b) Sam has to answer this question.
Sam writes \( 42.1 \times 10^{6}\) as his answer to this question.
What two errors has Sam made?
▶️ Answer/Explanation
(a) 2.73 × 10⁻³
Move decimal 3 places right for standard form.
(b) 1) 42.1 is incorrectly rounded [to 3 significant figures]
2) \( 42.1 \times 10^{6}\) is not correct standard form