WAEC Mathematics 2015 Paper

Concept:The whole land is treated as $1$, and each crop is subtracted step by step from the remaining portion.Explanation:Total land = $1$.Land used for cassava = $\frac{2}{5}$.Remaining land after cassava = $1 - \frac{2}{5} = \frac{3}{5}$.Land used for yam = $\frac{1}{3}$ of the remaining land = $\frac{1}{3} \times \frac{3}{5} = \frac{1}{5}$.Land used for cassava and yam together = $\frac{2}{5} + \frac{1}{5} = \frac{3}{5}$.Land used for maize = $1 - \frac{3}{5} = \frac{2}{5}$.Answer:The part of the land used for maize is $\frac{2}{5}$.The correct option is B. $\frac{2}{5}$.