Number of Functions Possible from Set a to Set B

Q. If |A|=|B|= 4, then the number of injections from A to B is

1. 12
2. 16
3. 20
4. 24

Q. The number of injections that can be defined from a set A consisting 5 elements to a set B consisting 6 elements is

1. 720
2. 360
3. 180
4. 90