某学生在整理班级同学的身高数据时,记录了10名同学的身高(单位:厘米)如下:152, 148, 155, 160, 158, 153, 149, 157, 161, 154。如果将这些数据按从小到大的顺序排列,则中位数是多少?
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解一元一次方程时,通常采用移项的方法,将含未知数的项移到等式一边,常数项移到另一边。由 3x - 6 = 2x + 1,正确的移项应为:3x - 2x = 1 + 6,即选项 B 所述。选项 A 移项时符号错误,选项 C 过早除以系数不符合常规步骤,选项 D 虽可接受但不是最直接的移项方式,而题目问的是‘接下来应该进行的正确步骤’,B 是最标准且合理的操作。
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[{"id":1074,"content":"在一次班级图书角整理活动中,某学生统计了上周同学们借阅图书的情况。其中,借阅科普类图书的人数比借阅文学类图书的人数多5人,两类图书共被借阅了37人次。设借阅文学类图书的人数为x,则根据题意可列出一元一次方程:________。","type":"填空题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"x + (x + 5) = 37","explanation":"根据题意,借阅文学类图书的人数为x,则借阅科普类图书的人数为x + 5。两类图书共被借阅37人次,因此总人数为文学类人数加上科普类人数,即x + (x + 5) = 37。这是一道基于一元一次方程知识点的应用题,考查学生将实际问题转化为数学方程的能力,符合七年级数学课程要求。","options":[]},{"id":294,"content":"在平面直角坐标系中,点A的坐标是(3, -2),点B的坐标是(-1, 4)。若点C是线段AB的中点,则点C的坐标是","type":"选择题","subject":"数学","grade":"初一","stage":"小学","difficulty":"简单","answer":"A","explanation":"根据平面直角坐标系中两点间中点坐标公式:若点A的坐标为(x₁, y₁),点B的坐标为(x₂, y₂),则中点C的坐标为((x₁ + x₂)\/2, (y₁ + y₂)\/2)。将点A(3, -2)和点B(-1, 4)代入公式,得:横坐标为(3 + (-1))\/2 = 2\/2 = 1,纵坐标为(-2 + 4)\/2 = 2\/2 = 1。因此,点C的坐标为(1, 1)。选项A正确。","options":[{"id":"A","content":"(1, 1)"},{"id":"B","content":"(2, 2)"},{"id":"C","content":"(1, 2)"},{"id":"D","content":"(2, 1)"}]},{"id":748,"content":"在一次班级环保活动中,某学生收集了若干千克废纸,第一天卖出了总量的三分之一,第二天又卖出了2千克,此时还剩下5千克。该学生最初收集的废纸共有___千克。","type":"填空题","subject":"数学","grade":"初一","stage":"小学","difficulty":"简单","answer":"10.5","explanation":"设该学生最初收集的废纸为x千克。根据题意,第一天卖出了x的三分之一,即(1\/3)x千克,第二天卖出了2千克,剩下5千克。可以列出方程:x - (1\/3)x - 2 = 5。化简得:(2\/3)x = 7。两边同时乘以3\/2,得到x = 7 × (3\/2) = 10.5。因此,该学生最初收集的废纸共有10.5千克。","options":[]},{"id":230,"content":"某学生在计算一个数减去5时,错误地算成了加上5,得到的结果是12。那么正确的计算结果应该是____。","type":"填空题","subject":"数学","grade":"初一","stage":"小学","difficulty":"简单","answer":"2","explanation":"根据题意,某学生将‘减去5’误算为‘加上5’,得到12。说明原数加上5等于12,因此原数为12 - 5 = 7。正确的计算应是7减去5,即7 - 5 = 2。所以正确答案是2。","options":[]},{"id":1960,"content":"某学生在研究某城市一周内的空气质量指数(AQI)变化时,记录了连续7天的AQI数据:45, 68, 52, 73, 60, 55, 80。为了分析这组数据的集中趋势,该学生计算了这组数据的中位数。请问这组AQI数据的中位数是多少?","type":"选择题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"中等","answer":"B","explanation":"本题考查数据的收集、整理与描述中中位数的概念与计算。中位数是一组数据按从小到大(或从大到小)排列后,处于中间位置的数。首先将AQI数据从小到大排序:45, 52, 55, 60, 68, 73, 80。由于共有7个数据(奇数个),中位数就是第4个数,即60。因此,这组数据的中位数是60。","options":[{"id":"A","content":"55"},{"id":"B","content":"60"},{"id":"C","content":"68"},{"id":"D","content":"73"}]},{"id":2777,"content":"高二示例题目","type":"选择题","subject":"通用","grade":"高二","stage":"高中","difficulty":"中等","answer":"示例答案","explanation":"示例解析","options":[]},{"id":130,"content":"小明在解一个一元一次方程时,将方程 3(x - 2) = 2x + 1 的括号展开后,写成了 3x - 6 = 2x + 1。接着他正确地移项并合并同类项,最终得到的解是 x = a。请问 a 的值是多少?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"7","explanation":"本题考查初一学生对方程变形和求解的掌握情况,涉及去括号、移项、合并同类项等基本代数操作。题目通过描述解题过程,引导学生关注方程求解的逻辑步骤,而非直接给出方程求解,具有一定的思维引导性。学生需要理解每一步变形的合理性,并正确执行计算。","options":[{"id":"A","content":"7"},{"id":"B","content":"8"},{"id":"C","content":"6"},{"id":"D","content":"3.5"}]},{"id":2132,"content":"某学生在解一个一元一次方程时,将方程中的常数项2误写成了-2,结果解得x = 3。若原方程的解应为x = -1,则这个一元一次方程可能是下列哪一个?","type":"选择题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"B","explanation":"根据题意,某学生将常数项2写成-2后解得x=3,说明错误方程为x - 2 = 1(因为3 - 2 = 1成立)。而原方程应为x + 2 = 1,此时解得x = -1,符合题设条件。其他选项代入x=-1均不成立,因此正确答案是B。","options":[{"id":"A","content":"2x + 2 = 0"},{"id":"B","content":"x + 2 = 1"},{"id":"C","content":"3x - 2 = 1"},{"id":"D","content":"x - 2 = -3"}]},{"id":2321,"content":"某学生在整理班级同学最喜欢的运动项目数据时,制作了如下频数分布表。已知喜欢跳绳的人数是喜欢踢毽子的2倍,且喜欢跳绳和踢毽子的总人数为36人。如果喜欢打篮球的人数比喜欢踢毽子的多6人,那么喜欢打篮球的有多少人?","type":"选择题","subject":"数学","grade":"八年级","stage":"初中","difficulty":"简单","answer":"A","explanation":"设喜欢踢毽子的人数为x,则喜欢跳绳的人数为2x。根据题意,跳绳和踢毽子的总人数为36人,可得方程:x + 2x = 36,解得x = 12。因此,喜欢踢毽子的有12人,喜欢跳绳的有24人。又知喜欢打篮球的人数比喜欢踢毽子的多6人,即12 + 6 = 18人。故喜欢打篮球的有18人,正确答案为A。","options":[{"id":"A","content":"18人"},{"id":"B","content":"20人"},{"id":"C","content":"24人"},{"id":"D","content":"30人"}]},{"id":172,"content":"小明在文具店买了一支钢笔和两本笔记本,共花费18元。已知每本笔记本的价格是5元,那么这支钢笔的价格是多少元?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"A","explanation":"根据题意,两本笔记本的总价为:2 × 5 = 10(元)。小明总共花费18元,因此钢笔的价格为:18 - 10 = 8(元)。所以正确答案是A选项。","options":[{"id":"A","content":"8元"},{"id":"B","content":"10元"},{"id":"C","content":"13元"},{"id":"D","content":"15元"}]}]