2010 AMC 8 Problem 9

Ryan got 80\% of the problems correct on a 25-problem test, 90\% on a 40-problem test, and 70\% on a 10-problem test. What percent of all the problems did Ryan answer correctly?

\textbf{(A)}\ 64 \qquad\textbf{(B)}\ 75\qquad\textbf{(C)}\ 80\qquad\textbf{(D)}\ 84\qquad\textbf{(E)}\ 86

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.