问题
填空题
布袋里有同样重量，同样大小的红球、绿球、黑球和白球各10个，至少要摸出______个球，才能保证有2个同色的球被取出．
答案
此题最坏情况是每种颜色摸1个，则无论如何下一个就会符合要求，
需要：1×4+1=5（次）；
答：至少应该摸5个才能保证至少有2个球颜色相同．
故答案为：5．
搜题请搜索小程序“爱下问搜题”
布袋里有同样重量，同样大小的红球、绿球、黑球和白球各10个，至少要摸出______个球，才能保证有2个同色的球被取出．
此题最坏情况是每种颜色摸1个，则无论如何下一个就会符合要求，
需要：1×4+1=5（次）；
答：至少应该摸5个才能保证至少有2个球颜色相同．
故答案为：5．
It is interesting to know what people of different nations like to be best. In France, when a woman enters a café or restaurant, she is freely discussed, not only about her appearance but about her past and future as well. She invites looks in the street whether she is beautiful or plain. There is no better way for a woman to get back her self-confidence than a walk in the streets of Paris or Marseilles, and woman really like that. In Italy, people love talking. They sit about in cafes, exchanging news and discussing politics. They do not hesitate to ask questions about the family, income and private life of anybody who happens to be there. The Swiss eat as a pastime. Ladies walk into a teashop, eat a couple of ice creams and a large piece of chocolate cake, and then leave, complaining about their weight.] For the Americans, the greatest fondness is said to be the push of buttons. You push a button in the lift, you push a button for cigarette, chewing gums, stamps, even for a life insurance. You can even push a button to get married and another button to get divorced. In England, waiting in a line is national passion. The English will form a line whether they have the opportunity or not. Long queues can be seen, for example, at stations when the train is practically empty and everybody can have a seat.
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