Can someone please help me with this?

Mary had at least an 80% on her test write an inequality to represent this situation

At the newest animated movie, for every 9 children, there are 4 adults. there are a total of 39 children and adults at the movie.

Apublic library wants to place 4 magazines and 9 books on each display shelf. the expression 4s+9s represents the total number of items that will be displayed on s shelves. simplify the expression