Halloween quizzes

Zelda the witch has all of her cats and all of her owls in the
house. She has 9 animals in the house and they have 30 legs
altogether. How many cats and how many owls does she have?


Frankenstein has 15 shirts in his wardrobe. They are all black or
blue. He has 7 more black shirts than blue ones. How many blue
shirts does he have?


Dracula, Frankenstein, Mummy, Gilda and Zelda are all having a
Halloween party. Each of them has given an invitation to all of
the others. How many invitations have been given out?