Sarah's grade was 50th percentile of the 20 grades for her class. Of the 30 grades from another class, 10 were higher than Sarah's, and the rest were lower. If no other grade was the same as Sarah's grade, then Sarah's grade was what percentile of the grades of the two classes of two classes combined?
Options:
(A) 52nd
(B) 56th
(C) 60th
(D) 70th
(E) 82nd Hmmm, my stream of consciousness:
52nd/56th/60th/70th/82nd So, the answer is (C).