Question

Let A be a finite set having x elements and let B be a finite set having y elements. What is the number of distinct functions mapping B into A.
1. x^y
2. 2^{(x + y)}
3. y^x
4. y! / (y - x)!

Answer 1

Correct Answer - Option 1 : x^y

The correct answer is Option 1

Set A have x elements and B set have y elements. Each element in B has x choices to be mapped to set A.

B → A

So total number of function = x.x.x.x.x.x.x ..........y times

So total number of function = x^y