Physics problem related to free-falling bodies?

Well if the hiker was the only one that noticed this boulder falling, then I am uming that he had a stopwatch that was accurate to within 0.1 sec. And without special equipment, how is he to know where exactly "the last third of the way" starts? Was he estimating that measurement? I would say that you shouldn't even need a calculator for this question because the amount of error in these two obvious guestimations are too high to even bother with.