Karl's mother buys 60 party favors to give out as gifts during Karl's birthday party. Which number of guests will not let her divide the party favors evenly among the guests?

1 guests = 60 favors each

2 guests = 30 favors each

3 guests = 20 favors each

4 guests = 15 favors each

5 guests = 12 favors each

6 guests = 6 favors each

7 guests = 8.571428 ... each

The answer is 7 guests because 7 is not a factor of 60 and so Karl's mother can't divide up her party favors to 7 guests without having to split them up (which she most likely doesn't want to do).

It's 25. It's the only one not a factor of 60.