Question

If $f:A\to B$ is a bijective function and if n(A) = 5, then n(B) is equal to

• A. 10
• B. 4
• C. 5
• D. 25

Answer 1

Answer: (C)

5

We are given $f$ is a bijective function.

It means $f$ is one-one as well as onto function.

Therefore every element of $B$ is a image in $f$.

$f$ is one-one therefore image of every element is different.

$\Rightarrow$ number of elements in $B$ should be equal to number of elements in $A$.

$\therefore n\left(B\right)=n\left(A\right)=5$

Option $\left(C\right)$ is correct.