BECE Mathematics 2015 Paper

Concept:Rewrite the decimal numbers as whole numbers multiplied by powers of $10$, then divide using the laws of indices.Explanation:Write $1.612$ as $1612 \times 10^{-3}$ because the decimal point moves 3 places to the right.Write $0.4$ as $4 \times 10^{-1}$ because the decimal point moves 1 place to the right.$\frac{1.612}{0.4} = \frac{1612 \times 10^{-3}}{4 \times 10^{-1}}$.Divide the whole numbers: $1612 \div 4 = 403$.For the powers of $10$, use $\frac{10^{-3}}{10^{-1}} = 10^{-3-(-1)} = 10^{-2}$.Therefore, $1.612 \div 0.4 = 403 \times 10^{-2}$.Move the decimal point in $403.0$ two places to the left: $403.0 \times 10^{-2} = 4.03$.Answer:B. $4.03$