JAMB Mathematics 2019 Paper

Concept:Simplify the complex fraction step by step, then apply the negative power by taking the reciprocal.Explanation:Start with $\left( \frac{6}{0.32} \div \frac{2}{0.084} \right)^{-1}$.Rewrite both decimals as fractions:$\frac{6}{0.32} = \frac{600}{32}$ and $\frac{2}{0.084} = \frac{2000}{84}$.So the expression becomes $\left( \frac{600}{32} \div \frac{2000}{84} \right)^{-1}$.Change division to multiplication by the reciprocal:$\left( \frac{600}{32} \times \frac{84}{2000} \right)^{-1}$.Simplify the product: $\frac{600 \times 84}{32 \times 2000} = \frac{63}{80}$.The expression is now $\left( \frac{63}{80} \right)^{-1}$.A negative index means take the reciprocal:$\frac{80}{63}$.Convert to a decimal: $\frac{80}{63} = 1.2698\ldots$Correct to 1 decimal place, this is $1.3$.Answer:$1.3$ (Option A).