So if 210=3.5 then 120 should be equals x. 210÷120=1.75 and 3.5÷1.75=2. At least thats is what I think.
As usual in life, motives can be complicated. The theme of Ivan Illych marrying this woman because of her money and her social position is one possibility that he discusses (she comes from a "good" family and has some property). The other theme is that she is pretty and he fell in love with her and to some extent she complements his views on life. In choosing from the options, re the themes, I would say that a) conforming to social conventions and b) the necessity of companionshp should be the two main themes in this excerpt.
Tell her parents and she runs to her parents and is saying water over and over
