Are any differences between Persons and People?
Both persons and people are the correct plual forms of person. They are used interchangeably, but their original purposes were different.
Persons was originally used when the number of persons could be easily counted:
Three persons ate lunch together.
People was used to describe a group in which the number of individuals was hard to count:
Many people went shopping yesterday.
Nowdays, we use people much more frequently than persons as the plural form of person. Therefore, "three people: is just correct as "three persons".