GMAT数学备考资料：练习+讲解（5）
<p> 下面<span word="GMAT">GMAT</span>思为大家整理了<span word="GMAT">GMAT</span>数学备考资料：练习+讲解（5），供考生们参考，以下是详细内容。</p><p> 6、一枚<span word="coin">coin</span>，投一次正面朝上的概率不是0.5，问是多少?</p><p> 正面朝上是正面朝下的概率的两倍;</p><p> 连续投两次，一次朝上一次朝下的概率是4/9;</p><p> 【答案】<span word="A">A</span></p><p> 【思路】设朝上的概率为<span word="X">X</span>，那么朝下的概率为1-<span word="X">X</span>;<span word="X">X</span>=2==<span word="X">X</span>=2/3</p><p> <span word="CX">CX</span>=4/9==<span word="X">X</span>=1/3 <span word="OR">OR</span> 2/3</p><p> 7、4<span word="s">s</span>, 6<span word="j">j</span>从中挑取3个，至少有1个<span word="s">s</span>，问多少咱挑法?</p><p> 【答案】100</p><p> 【思路】至少有1个<span word="s">s</span>，只要把总数中减去一个<span word="S">S</span>也没有就可以了。<span word="C">C</span>-<span word="C">C</span></p><p> 8、<span word="x">x</span>^3<span word="y">y</span></p><p> 根号<span word="x">x</span><span word="y">y</span></p><p> <span word="x">x</span><span word="y">y</span></p><p> 【答案】<span word="E">E</span></p><p> 【思路】举反例：<span word="X">X</span>=1/4 <span word="Y">Y</span>=1/3 <span word="AND">AND</span> <span word="X">X</span>=4 <span word="Y">Y</span>=1</p><p> <span word="X">X</span>=2 <span word="Y">Y</span>=1 <span word="AND">AND</span> <span word="X">X</span>=-2 <span word="Y">Y</span>=-3</p><p> +：<span word="X">X</span>=4 <span word="Y">Y</span>=1 <span word="AND">AND</span> <span word="X">X</span>=1/4 <span word="Y">Y</span>=1/7</p><p> 9、一个物体<span word="mass">mass</span>的1/81/7部分在水面上，问水上比水下<span word="range">range</span>是多少?</p><p> 【答案】1/71/6</p><p> 【思路】<span word="IF">IF</span> 水上部分为1/8，则水下为7/8，比为1/7;<span word="IF">IF</span>水上部分为1/7，则水下为6/7，比为1/6。所以范围为1/71/6</p><p> 10、<span word="x">x</span>^3-<span word="x">x</span> = ，且<span word="ac">ac</span>，问<span word="b">b</span>= ?</p><p> 【答案】0</p><p> 【思路】<span word="x">x</span>^3-<span word="x">x</span>=<span word="X">X</span>= ，又<span word="ac">ac</span></p>
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