1957 AHSME Problem 39

Two men set out at the same time to walk towards each other from M and N, 72 miles apart. The first man walks at the rate of 4 mph. The second man walks 2 miles the first hour, 2\tfrac {1}{2} miles the second hour, 3 miles the third hour, and so on in arithmetic progression. Then the men will meet:

\begin{array}{l} \textbf{(A)}\ \text{in 7 hours} \qquad \textbf{(B)}\ \text{in }{8\frac {1}{4}}\text{ hours}\qquad \textbf{(C)}\ \text{nearer }{M}\text{ than }{N}\qquad\\ \textbf{(D)}\ \text{nearer }{N}\text{ than }{M}\qquad \textbf{(E)}\ \text{midway between }{M}\text{ and }{N} \end{array}

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