Sets Practice Test 1

Concept:An ordered pair $(x,y)$ is included in set $A$ only when $x$ divides $y$ exactly.Explanation:We check each value of $x \in \{2,3,4\}$ against $y \in \{4,6,9,10\}$.For $x=2$: $2$ divides $4,6,10$, so the pairs are $(2,4),(2,6),(2,10)$.This gives $3$ pairs.For $x=3$: $3$ divides $6,9$, so the pairs are $(3,6),(3,9)$.This gives $2$ pairs.For $x=4$: $4$ divides only $4$, so the pair is $(4,4)$.This gives $1$ pair.Total number of elements in $A$ is $3+2+1=6$.Answer:Set $A$ contains $6$ elements, so the correct option is D.