陈向东《高分突破》疑难求解？？？？？

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陈向东《高分突破》疑难题求解：
69.从集合中取任意一个数，x从X集合中取，y从Y集合中取，求x/y的概率是一个整数?
——（3/8）
164．9个人photo排队，最矮的第一排，第二排中间为教练。one of the taller boys is known to misbehave；to keep him from disrupting the photo session。求排列的种类？
——（1440）

165．一顿午餐由，soup，salad，sandwich，coffee or tea，a desert。If the menu lists 3 soups,2 salads,7sanwiches and 8 deserts, how many different lunches you can shoose.(two lunches are different if they differ in any aspect)
——(560)
167．12个队伍，每队和其他队伍比赛一次。如果每个比赛由2支队伍进行，总的比赛数多少？
——（48）
188. seven basketball team play in a league against each other. At the end of the season, how many different arrangements are there for the top 3 teams in the rankings?
——(210)
200. A marketing firm determined that, of 280 households surveyed,90 used neither Brand A nor Brand B soap,70 used only Brand A soup, and for every household that used both brands of soap, 4 used only Brand B soap. How many of the 280 households surveyed used both brands of soaps?
——（40）

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