JAMB Mathematics 2021 Paper

Concept:Track the fraction of the whole basket that remains after each child takes their share.Explanation:Let the total number of mangoes be represented by $1$.The first child takes $\frac{1}{4}$, so the remainder is $1 - \frac{1}{4} = \frac{3}{4}$.The second child takes $\frac{3}{4}$ of this remainder.That is $\frac{3}{4} \times \frac{3}{4} = \frac{9}{16}$ of the whole basket.The fraction left for the third child is $\frac{3}{4} - \frac{9}{16}$.Since $\frac{3}{4} = \frac{12}{16}$, we have $\frac{12}{16} - \frac{9}{16} = \frac{3}{16}$.Answer:The third child took $\frac{3}{16}$, which is option A.