In front of you are ten bags, filled with marbles. The number of marbles in each bag differs, but all bags contain between 10 and 50 marbles. Nine of the ten bags only contain marbles of 10 grams each. One bag only contains marbles of 9 grams. In addition, you have a balance which can weigh in grams accurate, and you are allowed to use it only once (i.e. weigh a single time).

The question: How can you find out in one weighing which bag contains the marbles of 9 grams?

The answer: Click here!

Another question: Again, you have ten bags, filled with marbles. All bags contain between 100 and 200 marbles. Eight of the ten bags only contain marbles of 10 grams, and two bags only contain marbles of 9 grams. Again, you have a balance which can weigh in grams accurate, and you are allowed to use it only once. How can you find out in one weighing, which two bags contain the marbles of 9 grams?

Another answer: Click here!

Yet another question: Again, you have ten bags, filled with marbles. All bags contain 1000 marbles. Every bag contains either marbles of 9 grams or marbles of 10 grams. Again, you have a balance which can weigh in grams accurate, and you are allowed to use it only once. How can you find out in one weighing, which bags (if any) contain marbles of 9 grams?

Yet another answer: Click here!