UK Brebas Friend Photo Challenge
The Bebras Computing Challenge introduces computational thinking to students.
It is organised in over 40 countries and designed to get students all over the world excited about computing.
The challenge exposes children to a new subject and way of thinking. To develop their computational thinking skills, the children in computer club have been trying out some of the challenges published by UK Brebas including The Friend Photo Challenge. Why not have a go at solving one of these challenges yourself?
Lucia and her friends are part of an on-line social network.
Below is a diagram describing the relationships among Lucia and her friends. Each line indicates a friendship.
Lucia sends a photo to some of her friends.
Each of those friends sends the photo to all of their friends.
Which of the following groups of friends can Lucia send her photo to so that Jacob is not sent the photo?