Financial riddle

Financial riddle

John Bjarne Grover

I learnt this riddle in school but it may be that it is still not solved

3 friends went to a restaurant and had a pizza and paid 10 euros each. As they left, the restaurant owner got moral scruples and sent the boy after them with 5 euros because 30 was too much for such a pizza. The boy gave 1 euro to each of them and kept 2 for himself. Then each of them had paid 9 euros - that is 27 euros - plus the 2 which the boy kept. That makes for 29 euros. But where is the last euro?

Answer: It is in the moral scruples. (Is that really right? I believed moral scruples were gratis?)

Nazi philosophy claims perhaps that it is not in the moral scruples - it is in the boy.

Or is it simply in the pizza? That is perhaps the most probable solution: They had eaten it, and thereby it was divided equally among the three friends. That makes for a total of 30 euros, so the riddle should be solved?

Or is there an even simpler solution?

Could be all the science that can be made for solving the riddle is a waste of time: The restaurant had earned 25 euros - plus the 2 of the boy makes for the 27 of the three friends.