Question: My demand functions for goods 1 and 2 are ?1(?1, ?2, ?) and ?2(?1, ?2, ?

Question:

My demand functions for goods 1 and 2 are ?1(?1, ?2, ?) and ?2(?1, ?2, ?). If x1(2,5,90) = 20, x2(2,5,90) = 10, x1(2,4,90) = 15, and x2(2,4,90) = 15, can you say anything about how I would rank the commodity bundles (20,10) and (15,15)?

(Hint: This problem requires no calculus, algebra, or even arithmetic; just a little thinking.) 

My thinking is that the commodity bundles both equal 30, therefore they are equally ranked. Can i please have help?