Question

Let $A=\{1,3,4,7,11\}$, $B=\{1,1,2,5,7,9\}$ and $f:A\to B$ be given by $f$ $=\left\{\right(1,1),(3,2),(4,1),(7,5),(11,9\left)\right\}$. Then $f$ is

• A. One-one
• B. Onto
• C. Bijective
• D. Not a function

Answer 1

The correct option is A One-one

Given $A=\{1,3,4,7,11\}$, $B=\{1,1,2,5,7,9\}$ and $f=\left\{\right(1,1),(3,2),(4,1),(7,5),(11,9\left)\right\}$

Here , for each element in $A$ is mapped to a unique element in $B$, Hence the function $f$ is one -one.

Here for element $7$ in $B$, there is no corresponding element in $A$. Hence function is not onto.

As the function is one-one and not onto, $f$ is not bijective.