Direction: The following line graph carefully to answer these questions:

The following line chart shows the number of students in three different schools (A, B and C) in year 2017, 2018, 2019 and 2020.

What is the ratio of the students from school A, B and C together in 2019 to the number of students from school A in 2017, school B in 2018 and school C in 2019 together?