gre数学基本概念及实例解析(8)
<p> <span word="gre">gre</span>数学考试在新<span word="gre">gre</span>考试当中增加了一些难度，但是<span word="gre">gre</span>考生也不要太紧张，只要把一些<span word="gre">gre</span>数学基本概念掌握好，解题时就一定能轻松应对。</p><p> 独立重复试验的概率</p><p> 例题.某种天气预报准确率80%，连续预报7次，其中有6次准确的概率是多少?</p><p> 赔率<span word="odds">odds</span></p><p> 例题.<span word="The">The</span> <span word="odds">odds</span> <span word="in">in</span> <span word="favor">favor</span> <span word="of">of</span> <span word="winning">winning</span> <span word="a">a</span> <span word="game">game</span> <span word="can">can</span> <span word="be">be</span> <span word="found">found</span> <span word="by">by</span> <span word="computing">computing</span> <span word="the">the</span> <span word="ratio">ratio</span> <span word="of">of</span> <span word="the">the</span> <span word="probability">probability</span> <span word="of">of</span> <span word="winning">winning</span> <span word="to">to</span> <span word="the">the</span> <span word="probability">probability</span> <span word="of">of</span> <span word="not">not</span> <span word="winning">winning</span>. <span word="If">If</span> <span word="the">the</span> <span word="probability">probability</span> <span word="that">that</span> <span word="Team">Team</span> <span word="X">X</span> <span word="will">will</span> <span word="win">win</span> <span word="a">a</span> <span word="game">game</span> <span word="is">is</span> 5/8, <span word="what">what</span> <span word="are">are</span> <span word="the">the</span> <span word="odds">odds</span> <span word="that">that</span> <span word="Team">Team</span> <span word="X">X</span> <span word="will">will</span> <span word="win">win</span> <span word="the">the</span> <span word="game">game</span>?</p><p> <span word="A">A</span>.5 <span word="to">to</span> 3</p><p> <span word="B">B</span>.3 <span word="to">to</span> 8</p><p> <span word="C">C</span>.3 <span word="to">to</span> 5</p><p> <span word="D">D</span>.5 <span word="to">to</span> 8</p><p> <span word="E">E</span>.8 <span word="to">to</span> 3</p><p> 例题.<span word="Of">Of</span> <span word="the">the</span> <span word="books">books</span> <span word="in">in</span> <span word="a">a</span> <span word="certain">certain</span> <span word="room">room</span>, 50 <span word="are">are</span> <span word="written">written</span> <span word="in">in</span> <span word="German">German</span>, 65 <span word="are">are</span> <span word="in">in</span> <span word="Chinese">Chinese</span>, 120 <span word="are">are</span> <span word="in">in</span> <span word="Japanese">Japanese</span>, 50 <span word="are">are</span> <span word="in">in</span> <span word="French">French</span>, <span word="and">and</span> 150 <span word="are">are</span> <span word="in">in</span> <span word="English">English</span>. <span word="If">If</span> <span word="those">those</span> <span word="books">books</span> <span word="are">are</span> <span word="removed">removed</span> <span word="randomly">randomly</span> <span word="from">from</span> <span word="the">the</span> <span word="room">room</span>, <span word="how">how</span> <span word="many">many</span> <span word="must">must</span> <span word="be">be</span> <span word="removed">removed</span> <span word="to">to</span> <span word="ensure">ensure</span> <span word="that">that</span> 80 <span word="of">of</span> <span word="the">the</span> <span word="books">books</span> <span word="removed">removed</span> <span word="are">are</span> <span word="written">written</span> <span word="in">in</span> <span word="the">the</span> <span word="same">same</span> <span word="language">language</span>?</p><p> <span word="A">A</span>.80</p><p> <span word="B">B</span>.81</p><p> <span word="C">C</span>.159</p><p> <span word="D">D</span>.285</p><p> <span word="E">E</span>.324</p><p> 例题.<span word="Each">Each</span> <span word="of">of</span> <span word="the">the</span> <span word="integers">integers</span> <span word="from">from</span> 10 <span word="to">to</span> 19, <span word="inclusive">inclusive</span>, <span word="is">is</span> <span word="written">written</span> <span word="on">on</span> <span word="a">a</span> <span word="separate">separate</span> <span word="piece">piece</span> <span word="of">of</span> <span word="paper">paper</span> <span word="and">and</span> <span word="the">the</span> <span word="ten">ten</span> <span word="piece">piece</span> <span word="are">are</span> <span word="put">put</span> <span word="into">into</span> <span word="a">a</span> <span word="box">box</span>. <span word="If">If</span> <span word="the">the</span> <span word="pieces">pieces</span> <span word="are">are</span> <span word="then">then</span> <span word="drawn">drawn</span> <span word="the">the</span> <span word="numbers">numbers</span> <span word="on">on</span> <span word="two">two</span> <span word="of">of</span> <span word="the">the</span> <span word="pieces">pieces</span> <span word="drawn">drawn</span> <span word="will">will</span> <span word="have">have</span> <span word="a">a</span> <span word="sum">sum</span> <span word="of">of</span> 30?</p>
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