1963 AHSME Problem 19

In counting n colored balls, some red and some black, it was found that 49 of the first 50 counted were red. Thereafter, 7 out of every 8 counted were red. If, in all, 90 % or more of the balls counted were red, the maximum value of n is:

\textbf{(A)}\ 225 \qquad \textbf{(B)}\ 210 \qquad \textbf{(C)}\ 200 \qquad \textbf{(D)}\ 180 \qquad \textbf{(E)}\ 175

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