How did the vendor transfer the salt from his sack to the restaurant owner's sack? A poor vendor, who had just one sack with him, went to a restaurant to sell salt and sugar. However, since he was having just one sack and obviously he could not mix the salt and sugar, so he had poured in the salt first, tied the sack in the middle, and then filled the top portion of the sack with the sugar. But the restaurant owner decided to buy salt only as he did not have any requirement for sugar. How did the vendor transfer the salt from his sack to the restaurant owner's sack?