THE CHOPPING WOOD PROBLEM

Two men chopped wood all day long, both working at exactly the same rate. One worked straight through without stopping to rest. At the end of the day he had a sizeable pile of logs. The other man would chop for fifty minutes and then take a ten-minute break. At the end of the day he had a much larger pile. He did not work any faster after taking his breaks, nor did the first man work any slower as the day wore on. How was the second man able to chop more wood?

HINT:
He did something else during his breaks other than resting.

Answer:

During each ten-minute break he sharpened his ax.