Question

Let $E=\{1,2,3,4\}$ and $F=\{1,2\}$ then the number of onto functions from E to F is

• A. $14$
• B. $16$
• C. $12$
• D. $8$

Answer 1

Answer: (A)

$14$

Number of onto function from $E$ to $F.$

$E=\{1,2,3,4\}$ $F=\{1,2\}$

Number of function from $E$ to $F=2\times 2\times 2\times 2=16$

We have to exclude functions where $f\left(x\right)=1$ & $f\left(x\right)=2$.

$\therefore$ Total number of onto function $=16-2=14$.