Directions to Des Moines joke

A driver pulled up beside a rundown farmhouse. He got out and knocked at the door. A very old woman answered the door, and he asked her for directions to Des Moines. "Don't know," the woman said. He got back in his car and pulled away. Then he heard voices. He looked in his rearview mirror and saw the woman and an equally old man waving for him to come back. So he made a U- turn and drove up to them. "This is my husband," the old woman said. "He doesn't know how to get to Des Moines either."