please explain in baby steps how you arrive at the numbers inside venn diagram...

the part where I get stuck are the intersections..thank you

3. Mary McMath surveyed 200 students in a finite class. Thirty went to the movies, 50 went to football games, 40 went to the theatre, 10 went to the movies and football games, 25 went to the movies and the theatre, 20 went to football games and the theatre, and 10 went to all three. (Use a Venn diagram) a. How many of the finite students did not go to the theatre? b. How many of the students went to exactly two of the different events