Question

Let $A=\{1,2,3\}$ and $B=\{a,b\}$.Which of the following subsets of $A\times B$ is a mapping from $A$ to $B$

• A. $\{(1,a),(3,b),(2,a),(2,b)\}$
• B. $\{(1,b),(2,a),(3,a)\}$
• C. $\{(1,a),(2,b)\}$
• D. none of these

Answer 1

Answer: (A), (B), (C)

$\{(1,a),(3,b),(2,a),(2,b)\}$
$\{(1,b),(2,a),(3,a)\}$
$\{(1,a),(2,b)\}$

$A=\{1,2,3\}B=\{a,b\}A\times B=\{(1,a),(2,a),(3,a),(1,b),(2,b),(3,b)\}.$

$\{(1,a),(3,b),(2,a,)(2,b)\}\subset A\times B$

$\{(1,b),(2,a),(3,a)\}\subset A\times B$

$\{(1,a),(2,b)\}\subset A\times B$