I'm posting one puzzle, riddle, math, or statistical problem a day. Try to answer each one and post your answers in the comments section. I'll post the answer the next day. Even if you have the same answer as someone else, feel free to put up your answer, too!
Friday, November 09, 2007
Comes as an Accessory
What is it that goes with an automobile and comes with it; is of no use to it,and yet the automobile cannot move without it?