How to answer the question "tell me about yourself" in a Masters degree interview?
In this occasion, the interviewers want to know your background and your motivation of further study in this particular subject. They want to give the opportunity to the right person. 

For example, I was once involved in the admission interview (although I didn't have the final say in the decision making). Based on my observation, those who had strong motivation but average GPA won over those with weak motivation and high GPA.