A man has 3 wife's, each one has 3 houses, in one of houses for every wife his mother in law lives. He goes to first house with money, mother doubles it, he leaves half, he goes to second wife, mother doubles it again, he leaves the same amount as to first wife, he goes to third house and mother doubles it again, he leaves the same amount as to first one,but goes home with no money. How much money did he have? 2 wife are sister and they have a same mother?
The riddle "Three Houses and Three Wives" is unanswered.
Có một sợi dây nếu đốt cháy hết từ đầu này sang đầu kia thì mất 10 phút. Sợi dây này không đồng chất, có đoạn cháy nhanh, đoạn cháy chậm. Bạn có trên tay một cái bật lửa, hỏi làm thế nào để đốt cháy hết được sợi dây sau 5 phút?