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用分步乘法计数原理分析一件与顺序无关的事时,若同一组中的元素异步而至,使组中本来无序的、平等和谐的元素,不知不觉地就带上了分步所产生的先后顺序,你能判断分步排列元素顺序的是与非吗?一、不同元素分步分配到同一组中例1在8张奖券中有一、二、三等奖各1张,其余5张无奖.将这8张奖券分配给4个人,每人2张,则不同的获奖情况有______种.(用数字作答)解(解法1)分两步分配:第一步从3张奖券中取出2张,分给4个人中的2个人,每人1张,有C_3~2A_4~2种方法;第二步分剩下的1张奖券,有C_4~1种方
Using the principle of step-by-step multiplication counting to analyze an event that has nothing to do with the order, if the elements in the same group asynchronously come into being, the disordered, equitable and harmonious elements of the group are unknowingly brought step by step First, the different elements are assigned to the same group step by step. Example 1 There are one of the first, second and third prizes in each of the eight lotteries, and the remaining five Zhang No Prize. The 8 lottery tickets will be allocated to 4 individuals, 2 per person. There will be ______ for different awards. (Solution 1) Solution (Solution 1) Distribute in two steps: Step 1 from 3 Zhang lottery tickets out of 2, divided into 2 of 4 individuals, each one, there are C_3 ~ 2A_4 ~ 2 kinds of methods; the second step the remaining one lottery coupons, C_4 ~ 1 kind of side