优优班--学霸训练营 > 知识点挑题
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            • 1.

              若\(A_{n}^{3}{=}12C_{n}^{2}\),则\(n{=}({  })\)

              A.\(8\)                                
              B.\(7\)                                
              C.\(6\)                                
              D.\(4\)
            • 2.

              \(What is the value of_{7}C_{2}\)

              A.    \(2520\)     
              B.\(49\)          
              C.\(42.\)       
              D.\(21\)
            • 3.

              \({C}_{2}^{2}+{C}_{3}^{2}+{C}_{4}^{2}+\cdots +{C}_{10}^{2}\)等于(    )

              A.\(990\)
              B.\(165\)
              C.\(120\)
              D.\(55\)
            • 4.
              现有\(5\)道试题,其中甲类试题\(2\)道,乙类试题\(3\)道,现从中随机取\(2\)道试题,则至少有\(1\)道试题是乙类试题的概率为             
            • 5.

              若\(C_{25}^{2x}{=}C_{25}^{x{+}4}\),则\(x\)的值为\(({  })\)

              A.\(4\)                        
              B.\(7\)                        
              C.\(4\)或\(7\)                 
              D.不存在
            • 6.

              圆周上有\(12\)个不同的点,过其中任意两点作弦,这些弦在圆内的交点的个数最多是(    )

              A.\(A\rlap{^{4}}{_{12}}\)   
              B.\(A\rlap{^{2}}{_{12}}A\rlap{^{2}}{_{12}}\)
              C.\(C\rlap{^{2}}{_{12}}C\rlap{^{2}}{_{12}}\)   
              D.\(C\rlap{^{4}}{_{12}}\)
            • 7.

              已知\(C_{14}^{m-1}+C_{14}^{m}=C_{15}^{m-3} \),则正整数\(m\)的值为            

            • 8.
              今有\(2\)个红球、\(3\)个黄球、\(4\)个白球,同色球不加以区分,将这\(9\)个球排成一列有__________种不同的方法\(.(\)用数字作答\()\)
            • 9.

              从\(5\)台甲型和\(4\)台乙型电视机中任意取出\(3\)台,其中至少要有甲型与乙型电视机各\(1\)台,则不同的取法共有________种\((\)用数字作答\()\).

            • 10.

              中任取个不同的数,则取出的个数之差的绝对值为的概率是(    )

              A.
              B.
              C.
              D.              
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