一只不透明的袋子中有1个白球和2个红球，这些球除颜色外都相同，搅匀后从中任意摸出1个球，记下颜色后放回袋中并搅匀，再从中任意摸出一球记下颜色，请利用表格或树状图分析两次都是红球的概率和两次一红一白的概率哪个大？
根据题意画出相应的树状图，如图所示：
所有的可能为：（白，红），（白，红），（红，白），（红，红），（红，白），（红，红）共6种，
两次都为红的占了2种，一红一白占了4种，
则P两红=
=2 6
，P一红一白=1 3
=4 6
，2 3
∵
＜1 3
，2 3
∴两次都是红球的概率比两次一红一白的概率小．
电脑和手机上有各种游戏，有的游戏能在某些方面帮助我们。请为以下各人搭配合适的游戏。（其中有一项是多余的。） 小题1:Peter isn’t good at geography, and he doesn’t like spending time on it. His parents want to help him. They have a good idea and make him interested in geography through games. 小题2:Lily is a five-year-old girl. She is very clever and likes remembering different flags. Although she is young, she can recognize lots of flags of different countries. 小题3:Mr White will take his daughter Kitty to go on a trip. He wants Kitty to choose the place. But Kitty is too young to know the cities, so Mr White finds a game to help her. 小题4:Tom’s fingers are not so quick. His doctors asks him to play some race games, such as the car race and the boat race. 小题5:Alan likes rafting. He goes rafting almost every month. Even when he plays games, he plays the one about rafting.
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