1952 AHSME Problem 32

K takes 30 minutes less time than M to travel a distance of 30 miles. K travels \frac {1}{3} mile per hour faster than M. If x is K's rate of speed in miles per hours, then K's time for the distance is:

\textbf{(A)}\ \dfrac{x + \frac {1}{3}}{30} \qquad \textbf{(B)}\ \dfrac{x - \frac {1}{3}}{30} \qquad \textbf{(C)}\ \frac{30}{x+\frac{1}{3}}\qquad \textbf{(D)}\ \frac{30}{x}\qquad \textbf{(E)}\ \frac{x}{30}

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