he following problem was presented at the end of a lesson in 9th grade, as something they could puzzle over:
The lightest of 8 outwardly alike coins is to be determined through weighing them as few times as possible. We know of exactly one coin being faked and we are given a scale, without any scale of measures.
After a short time of consideration Amin mentions that it is pretty much he same as the goat-wolf-cabbage-problem. The problem written in scrolls from the 8th century goes as follows
Once upon a time a man had to get a wolf, a goat and a cabbage across a river by boat. The boat however could only fit the man and the wolf or the goat or the cabbage. The wolf eats the goat, if left behind with the goat and no human supervision. The goat is going to eat the cabbage, if left behind with the cabbage. Only at the presence of a person none will eat the other. The man still managed to get all of them across the river. How did he do this?
Amin remembered another situation and discovered similarities - even at a high level of abstraction. The general idea of laying something aside, not using all objects at once, could have led up to that association. The scale problem is about a procedure of steps, and the coins have to be divided into three separate amounts:
Two amounts of three are compared to each other on the scale, so they are "in the boat". A pair that was set aside gets used according to the result of the weighings. Only two weighings are necessary to find the coin searched for.
Armin transferred a former experience of problem solving to a completely different situation. In this particular situation he proved to have an agile mind.
Oliver's reaction to Armin was amazed: "How is it you know something like that?"
Oliver would have loved to solve the problem just as quickly, maybe even posing the question: Can something like that be learned? Amin remarked that he has been solving riddles for a long time.