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North Cheshire Jewish Primary School

North Cheshire

Jewish Primary School

UK Bebras- Phone Messages Challenge

The Bebras Computing Challenge introduces computational thinking to students. 
It is organised in over 40 countries and designed to get children all over the world excited about computing.

The challenge exposes pupils to a new way of thinking. To develop their computational thinking skills, the children in computer club have been trying out a couple of the challenges published by UK Bebras. Why not have a go at one of them yourself?

Phone Messages

A class at Bebras High School has 39 students. The phone list shown below is used to pass along messages from the teacher. Blue boxes correspond to students. Black lines connect each person with the people that they must pass the messages to.

Each phone call lasts three minutes. Each person can only talk to a single person on the phone at a time.

When the teacher starts the first phone call to announce a message, how many minutes go by until the message is completely delivered to all 39 students?

Phone Messages Chart