Pens and pencils

Brenda, Pamela, Alice and Kitty go into a shop.

One girl buys a pen and a pencil.

One girl buys a pen and a book.

One girl buys a pencil and a book.

One girl buys two pencils.

Brenda buys a pen and one other thing.

Pamela buys a book and one other thing.

Alice doesn't buy a book or a pen.