A hobo who does like to smoke cigars but does not have any money, collects cigars stumps. From every six stumps he finds he can make a new cigar. One a particular day he finds 36 stumps. How many cigars can he smoke on that day?

Sarah and Mike conclude that it is wednesday. But five minutes later it is already friday. How is that possible?

If you would fold a letter in two fifty times, how thick should the enveloppe be that can fit the letter? Assume that the thickness of a piece of paper is about 0.05 mm.