题干

某慈善机构举办一次募捐演出,有一万人参加,每人一张门票,每张100元.在演出过程中穿插抽奖活动.第一轮抽奖从这一万张票根中随机抽取10张,其持有者获得价值1000元的奖品,并参加第二轮抽奖活动.第二轮抽奖由第一轮获奖者独立操作按钮,电脑随机产生两个数x,y(x,y∈{1,2,3}),随即按如下所示程序框图运行相应程序.若电脑显示“中奖”,则抽奖者获得9000元奖金;若电脑显示“谢谢”,则不中奖.



(Ⅰ)已知小曹在第一轮抽奖中被抽中,求小曹在第二轮抽奖中获奖的概率;

(Ⅱ)若小叶参加了此次活动,求小叶参加此次活动收入(含门票)的期望.

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解:(Ⅰ)从1,2,3三个数字中有重复取2个数字,其基本事件有(1,1),(1,2),(1,3),(2,1),(2,2),(2,3),(3,1),(3,2),(3,3)

共9个,设“小曹在第二轮抽奖中获奖”为事件A,且事件A所包含的基本事件有(3,1),(3,3)共2个,∴ P(A)

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    As a child, I started learning to play to piano, my favorite musical 1 , but I was forced to give up when I started my middle school 2I could concentrate more on my studies.

    It's one of my biggest 3 to stop practicing the piano when I recall sadly today. During the following years, I kept telling my piano teacher that I would 4. However, I didn't keep my promise because I was 5 with my study.6 I lost touch with my teacher. Some years later, my teacher died. I was very sad because I lost such a good teacher. She was a very warm and gentle person. It hurts me to think she may have been 7 that I never returned. I haven't taken lessons since then but to be honest, I 8 to. Sitting at the piano, I couldn't help recalling many 9—times of my practising at home and playing before my teacher and one time my teacher 10 me after I played entire pieces of music wrong in front of her colleagues. I was so 11 that I could hardly say anything. But her 12 helped ease my shame. These memories,13, good or bad, never caused my 14 for playing the piano again.

    This thought then led me to think that 15 is like music, and that we all try to play different 16 in the instrument of our life. Sometimes the pitch(音高) is 17 when we play it well, but sometimes we are out of tone. However, we all continue to create our own 18 style of music. No matter what style our music is, it is 19 that we sing the songs of joy, quietness and love. Though I may never make it back to piano lessons, it doesn't 20 that I've stopped making music.