WAEC Mathematics 2013 Paper

Concept:$X \cap Y^{1}$ represents the elements that are in $X$ but not in $Y$. In the Venn diagram, this is the part of circle $X$ that lies outside circle $Y$.Explanation:From the Venn diagram, circle $X$ contains two separate regions.The overlapping region contains elements that belong to both $X$ and $Y$.The other region, which is $X \cap Y^{1}$, contains the elements that belong only to $X$.In the diagram, this region is shown to contain $2$ elements.Therefore, the required number is $n(X \cap Y^{1}) = 2$.Answer:A. 2