The answer your looking for is B.
So first times $5x20=$100. now minus $217-$100=1=$117. then you divide $117/$3=39. so your answer they sold 59 tickets that night.
Hard to judge without the context of the other sentences of the story but if I had to guess, it sounds "inviting and familiar" to me.
I think the answer is that Sarah should look up words she doesn't know for chapter titles, headings and first paragraphs and write the main idea in her own words.