英语奥数真题及答案英语奥数真题及答案1、Didyouknow?Inthedecimalnumbersystem(base10)tendifferentdigits,0to9,areusedtowriteallthenumbers.Inthebinarynumbersystem(base2)twodifferentdigitsareused,i.e.0and1.Whichoneofthefollowingnumbersisnotavalidnumberintheoctalnumbersystem(base8)?A)128B)127C)126D)125E)1242、Thenumberofdiagonalsthatcanbedrawninaregularpolygonwithtwentysides(icosagon)is_____.3、Ifaandbareintegers,10?3=1,152?7=3,andthen379?6isequalto_____.4、Twonumbersareintheratio2:3.When4isaddedtoeachnumbertheratiochangesto5:7.Thesumofthetwooriginalnumbersis____.5、ThegreatestnumberofMondayswhichcanoccurin45consecutivedaysis____6、Saulplaysavideogameinwhichhescores4forahitandlost6foramiss.After20roundshisscoreis30.Thenumberoftimeshehasmissedis____.7、ThreegirlsA,BandCrunina100mrace.WhenAfinishes,Bis10mbehindAandwhenBfinishesCis20mbehindB.HowfarinmetreswasCfromAwhenAfinished?(Let’sassumealltheathletesrunataconstantspeed)8、Theareasofthefacesofarectangulaboxare84cm2,70cm2and30cm2.Thevolumeoftheboxincm3is____.9、Youhave3weights:1kg,3kgand9kgaswellasanequalarmbalance,asshown.Howmanydifferentweightobjectscanyouweighwiththesethree?[Remembertheweightsmaybeplacedoneitherside]参考答案：1、A考察我们学过的简单的.进制问题，显然8进制中没有8出现2、170找规律，公式为n×(n-3)÷23、1定义新运算，就是求379÷6的余数。4、40，16和245、76、57、28米，根据距离比求出速度比，三者的速度比为1：9/10：18/258、420分解质因数9、13种