BECE Mathematics 2021 Paper

Concept:Equal sets contain exactly the same elements, so any element missing from one set must be present in the other.Explanation:Given $P=\{4,8,12,16,20\}$ and $Q=\{16,4,12,k,20\}$.Since $P=Q$, every element of $P$ must appear in $Q$.Compare the known elements of $Q$ with those of $P$.$Q$ has $4$, $12$, $16$, and $20$, which all belong to $P$.The only element of $P$ not yet present in $Q$ is $8$.Thus, the unknown element $k$ must be $8$.Check: $Q=\{16,4,12,8,20\}$ is the same set as $P$.Answer:$k = 8$Correct option: C. 8