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, November 30, 2009
There are 12 balls.
11 of the balls weigh the same.
1 of the balls is either heavier or lighter than the rest.
You have an unmarked balance scale.
Using the scale only 3 times, determine which ball is different and whether it is heavier or lighter than the rest.