The tortoise and the hare are having a race over a course of length 0.52 km. The tortoise crawls along at a constant 0.075 m/s while the hare sprints along at a constant 16.7 m/s (when he is not sleeping). The race starts and the hare runs halfway to the finish line and decides to take a nap while the tortoise plods along. Waking from his nap, the hare sees that the tortoise has made so much progress that he might lose the race. He takes off and just catches up to the toroise at the finish line so that the race ends in a tie. Be careful with units.

How many hours did the hare sleep before waking up?