Once upon a time (about 450 b.c.), a Greek named Zeno made up several word problems that became known as Zeno’s paradoxes. This problem is not a paradox, but was inspired by one of Zeno’s problems. Consider a race between Achilles and a tortoise. The tortoise has a 100-meter head start. Achilles runs at a rate of 10 meters per second, whereas the tortoise runs 1 meter per second (it is an extraordinarily swift tortoise). How long does it take Achilles to catch up with the tortoise?