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!
Monday, August 15, 2011
Two brothers we are, great burdens we bear, all day we are bitterly pressed; Yet this I will say – we are full all the day, and empty when we go to rest. What are we?