GRE数学常见易错难题105道
<p> 1. <span word="n">n</span>个数从小到大排列，求（<span word="n">n</span>-1）/4，设商为<span word="i">i</span>，余数为<span word="j">j</span> ，则可求得1<span word="st">st</span> <span word="Quartile">Quartile</span>为：（第<span word="i">i</span>+1个数）（4-<span word="j">j</span>）/4+（第<span word="i">i</span>+2个数）<span word="j">j</span>/4</p><p> 2. 4个，2个的排列方式 15（=）</p><p> 3 .5双袜子，同时去2只，刚好配对的概率。1/9</p><p> 4. 40人说<span word="French">French</span>，60人说<span word="Russian">Russian</span>，80人说<span word="Italy">Italy</span>，说两种语言的有50人，说三种语言的有 10人。 共有125人，问不说这些语言的有几人。 <span word="Key">Key</span>:125-（40+60+80-50-102）=15</p><p> 5 。等腰直角三角形边长2加2倍根号2，求面积。</p><p> 6. 某种溶液浓度为125<span word="gram">gram</span> <span word="per">per</span> <span word="liter">liter</span>， 转换成 <span word="ounce">ounce</span> <span word="per">per</span> <span word="gallon">gallon</span>，求表达式。已知 1 <span word="ounce">ounce</span>=28.<span word="xxx">xxx</span> <span word="gram">gram</span> <span word="and">and</span> 1 <span word="gallon">gallon</span>=3.875 <span word="liter">liter</span></p><p> 7. <span word="x">x</span>，<span word="y">y</span>，<span word="z">z</span> 均方差为<span word="d">d</span>， 求<span word="x">x</span>+10，<span word="y">y</span>+10，<span word="z">z</span>+10的均方差 （<span word="d">d</span>）</p><p> 8. 1的概率是0.8，2的概率是0，6，问是1或是2或是<span word="both">both</span>的概率，1-0.60.8（数字瞎编）=0.92.</p><p> 9. 还有一组测量数据中，12.1比<span word="mean">mean</span>低1.5个标准差，17.5比<span word="mean">mean</span>高3.0个标准方差。问<span word="mean">mean</span>是多少.13.9（设标准差为<span word="X">X</span> 12.1+1.5<span word="X">X</span>=<span word="M">M</span>，17.5-3<span word="X">X</span>=<span word="M">M</span>）</p><p> 10. 图表题，1992年总和是50，96年是60，每年至少增长1，问最大的年增长：7.0</p><p> 11 .<span word="x">x</span>+<span word="y">y</span>=52<span word="x">x</span>+2<span word="y">y</span>=8之间最短距离与1比较 《1</p><p> 12. 以40<span word="miles">miles</span>/<span word="hour">hour</span>速度经过一1.5<span word="miles">miles</span>的路，若超速则罚款<span word="fine">fine</span>=50+（速度-40）10，现一人用108秒通过此路，问她的<span word="fine">fine</span>=？ <span word="key">key</span> 150</p>
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