Question

# The number of one - one functions that can be defined from into is

- 12
- 24
- 18
- 26

Hint:

### An **injective function** (injection) or one-to-one function is a function that maps distinct elements of its domain to distinct elements of its codomain.

One-to-One functions define that each element of one set, say Set (A) is mapped with a unique element of another set, say, Set (B).

## The correct answer is: 24

### Given : Two functions and

One-to-One functions define that each element of one set, say Set (A) is mapped with a unique element of another set, say, Set (B).

Each element of set A will pair with one element from set B and other elements of set A cannot pair with the paired element of A.

Thus, number of one - one function is 4! = 24

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