Question

If $A$ is the set of even natural numbers less than $\text{8}$ and $B$ is the set of prime numbers less than $\text{7}$ , then the number of relations from $A$ to $B$ are

• A. $2^{9}$
• B. $9^{2}$
• C. $3^{2}$
• D. $2^{9 - 1}$

Answer 1

Answer: (A)

$A=\left\{\right.2,4,6\left.\right\}$ ; $B=\left\{2 , 3 , 5\right\}$
$\therefore $ $A\times \, B$ contains $3\times 3=9$ elements.
Hence, the number of relations from $A$ to $B=2^{9}$ .