Steve is collecting toy cars. He already has 100 of them! 42 of them are new, 19 are his favorites; 3 are new and a favorite. Steve is going to donate to his school's yard sale all of them that neither new nor favorite. How many toy cars will he donate?

42

Step-by-step explanation:

This can be done with a Venn diagram, but I can't draw it here, so I'll explain it.

Of the 42 new ones, 3 are also his favorite. That means there are 39 new that are not favorite.

Of the 19 favorites, 3 are also new, so 16 are favorite but not new.

New but not favorite: 39

Favorite but not new: 16

New and favorite: 3

Total above: 39 + 16 + 3 = 58

He has a grand total of 100 toy cars, so 100 - 58 = 42

42 are neither new nor favorite.