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2019年6月2日场次gre数学预测发布,详细内容包括对6月2日GRE数学各大高频考点题型的具体讲解和解题思路剖析,确保考生不在简单数学部分意外失分,顺利拿到高分满分!
题目1.Aboxcontains100balls,numberedfrom1to100.Ifthreeballsareselectedatrandomandwithreplacementfromthebox,whatistheprobabilitythatthesumofthethreenumbersontheballsselectedfromtheboxwillbeodd?
A.1/4
B.3/8
C.1/2
D.5/8
E.3/4
答案:C
解析:本题因为奇数和偶数个数相同,和也只有两种方式,所以三个数的和为奇数的可能性为1/2。也可以考虑从这100个数中任取三个数的奇偶,可能性为:奇奇奇,奇偶偶,奇奇偶和偶偶偶,其中奇奇奇和奇偶偶两种情况的和为奇数,所以也得到可能性为1/2
2.Thereare1200respondentstoapoll,eachfavoringtheirpreferenceforcandidatesA,B,andC.54%favoredA,48%favoredB,and42%favoredC,andthereis30%favoredbothAandB.What’sthelargestpossiblenumberofrespondentsfavoringC,butnotC&B,norC&A?
A.25%
B.30%
C.28%
D.38%
E.40%
解析:A和B的并集为:54%48%-30%=72%,所C为28%
3.Inaninsurancecompany,eachpolicyhasapaperrecordandanelectricrecord.Forthosepolicieshavingincorrectpaperrecord,60%alsohavingincorrectelectricrecord;Forpolicieshavingincorrectelectricrecord,75%alsohavingincorrectpaperrecord.3%ofallpolicieshavebothincorrectpaperandincorrectelectricrecords.Ifwerandomlypickoutonepolicy,what’stheprobabilitythattheonehavingbothcorrectpaperandcorrectelectricrecords?A.0.80
B.0.94
C.0.75
D.0.88
E.0.92
答案:B
解析:设总数为x,设incorrectpaperrecord有y,incorrectelectricrecord有z,则:
x·y·60%=3%·xy=5%
x·z·75%=3%·xz=4%
则,两者至少有一个错误的百分比为5%4%-3%=6%,所正确答案为94%
4.IfBobcandoajobin20daysandJanecandothejobin30days,theyworktogethertodothisjobandinthisperiod,Bobstopworkfor2.5daysandJanestopworkforxdays,andthejobbefinishedfor14days,whatisx?
A.1.6
B.3.2
C.1.5
D.1.25
E.1.15
答案:D
解析:
1/20(14-2.5)1/30(14-x)=1,得出x=1.25
5.TheprobabilityofAis60%andtheprobabilityofBis50%,whatisthemostpossibleprobabilitythatneitherAnorBwouldhappen?B.0.40
D.0.55
E.0.68
解析:划出图表来可以一目了然:A,B均不发生的很大概率为40%,很小概率为0.因此选B