French test

What was the average score in this French test?
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative


The first four students to take a French test get an average of 4 marks.

The next six students to take the same test get an average of 6 marks.

What is the average for all 10 students?

This problem is taken from the World Mathematics Championships