A mathematician, a physicist and an engineer are led into a long room. At the other end stands a beautiful naked woman. “When I ring this bell,” she says" you may cross half the space between us. When I ring the bell again, you may again cross half the space between us." Both the mathematician and physicist groan and wander off. “Ah, it’s Zeno’s paradox, we can never actually reach her.” The engineer, waiting for the bell, says “I think I can get close enough.”

why is there a naked woman?

For the joke to work.

Could she have worn a skimpy bikini instead?