Question

The Number of one-one and onto functions that can be defined {$1,2,3,4$} onto set B is $24$ then $n\left(B\right)$ is

• A. 4
• B. 2
• C. 3
• D. 6

Answer 1

Answer: (A)

4

n(B)=4 because A={1,2,3,4} has 4 element

and $f:A\to B$ are one-one-onto fraction

then B must have 4 element.