Friday, November 7, 2008

动动脑筋!

来个小小的难题。难度: * * * (最难是5星)

这里有12个布袋,装了数量不一的金币。有其中一袋是假金币。真金币每棵重10克,而假金币每棵则重9克。怎样在只需秤一次的情形下,认定那一袋是装着假金币?

How to Solve?

There are 12 bags filled with unequal quantity of gold coins. However, among the 12, 1 of the bag contains fake gold coin. The mass of each of the real gold coin and fake gold coin is 10 gram and 9 gram respectively. How to determine which bag contains fake gold coin by just using the weight once?

5 comments:

Anonymous said...

Arrange the bags according to their number of coins, in ascending order, label them if you want from 1-12

Take 1,2,3...coin from the 12 bags respectively, there will be 1+2+3+4+5+6+7+8+9+10+11+12=78 coins

Weight those coins that are taken out
Deduct the weight taken from 780 (78*10)the remainder will indicate which bag contains of fake coins :)

Snakey said...

Correct! :)

Anonymous said...

只要有看过金田一漫画的都会,其中一个故事有讲到这个……

Snakey said...

看来你也是金田一读者。。。

Key said...

哈哈。。。我也看过,
还想抢答,可是太迟了。。。