1959 AHSME Problem 12

By adding the same constant to 20,50,100 a geometric progression results. The common ratio is: \textbf{(A)}\ \frac53 \qquad\textbf{(B)}\ \frac43\qquad\textbf{(C)}\ \frac32\qquad\textbf{(D)}\ \frac12\qquad\textbf{(E)}\ \frac{1}3

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