ʱ : һ 2015年全国高考数学试题分类汇编?1.2 古典概型与几何概?- 百度文库ϿʼĶ
.
11.2ŵ뼸θ
һ ŵ
1.(2015α,4,5)3Ϊһֱߵı߳,3Ϊһ鹴.1,2,3,4,5ȡ3ͬ,3һ鹴ĸΪ( ) A.10
3
B.5 1
C.10 D.20
11
C
2.(2015㶫,7,5)֪5Ʒ2Ʒ,ΪϸƷ.ִ5Ʒȡ2,ǡһƷĸΪ( ) A.0.4
B.0.6
C.0.8
D.1
B
14.(2015,15,13)סҡƹЭ˶ԱֱΪ27,9,18.ֲ÷ֲķЭгȡ6˶ԱӲμӱ. (1)ӦЭзֱȡ˶Ա;
(2)ȡ6˶Աб,ŷֱΪA1,A2,A3,A4,A5,A6.ִ6˶Աȡ2˲μ˫. (i)гпܵĽ;
(ii)AΪ¼ΪA5A6˶Ա1˱鵽,¼Aĸ.
(1)ӦӼסҡЭгȡ˶ԱֱΪ3,1,2. (2)(i)6˶Աȡ2˲μ˫пܽΪ
{A1,A2},{A1,A3},{A1,A4},{A1,A5},{A1,A6},{A2,A3},{A2,A4},{A2,A5},{A2,A6},{A3,A4},{A3,A5},{A3,A6},{A4,A5},{A4,A6},{A5,A6},15.
.
(ii)ΪA5A6˶Ա1˱鵽пܽΪ{A1,A5},{A1,A6},{A2,A5},{A2,A6},{A3,A5},{A3,A6},{A4,A5},{A4,A6},{A5,A6},9.
,¼AĸP(A)=15=5.
15.(2015ɽ,16,12)ijѧijȫ45ͬѧμ鷨źݽŵ,±:(λ:)
μݽ δμݽ μ鷨 8 2 δμ鷨 5 30 9
3
(1)Ӹðѡ1ͬѧ,ͬѧٲμһŵĸ; (2)ڼȲμ鷨ֲμݽŵ8ͬѧ,5ͬѧ
A1,A2,A3,A4,A5,3ŮͬѧB1,B2,B3.ִ5ͬѧ3Ůͬѧиѡ1,A1ѡB1δѡеĸ.
(1)ɵݿ֪,δμ鷨δμݽŵ30, ٲμһŵĹ45-30=15,
ԴӸðѡ1ͬѧ,ͬѧٲμһŵĸΪP=45=3. (2)5ͬѧ3Ůͬѧиѡ1,һпܵĽɵĻ¼:
{A1,B1},{A1,B2},{A1,B3},{A2,B1},{A2,B2}, {A2,B3},{A3,B1},{A3,B2},{A3,B3},{A4,B1}, {A4,B2},{A4,B3},{A5,B1},{A5,B2},{A5,B3}, 15.
,Щ¼ijǵȿܵ.
¼A1ѡB1δѡСĻ¼:
151
.
{A1,B2},{A1,B3},2.
A1ѡB1δѡеĸΪP=15.
16.(2015,18,12)ȫںָǺýйӰۺָ.رṩȫ2015ijȫԴͻġʡ̨ںָ,ǰ20ġʡ̨ںָзͳ,ʾ.
1 2 3 4 [4,5) [5,6) [6,7) [7,8] Ƶ 2 8 7 3 2
(1)ִںָ[4,5)[7,8]ڵġʡ̨ȡ2ҽе,1ҵںָ[7,8]ڵĸ;
(2)ݷͳƱ20ҡʡ̨ںָƽ. (1)ⷨһ:ںָ[7,8]ڵġʡ̨ΪA1,A2,A3;ںָ[4,5)ڵġʡ̨ΪB1,B2.ںָ[4,5)[7,8]ڵġʡ̨ȡ2ҵл¼
:{A1,A2},{A1,A3},{A2,A3},{A1,B1},{A1,B2},{A2,B1},{A2,B2},{A3,B1},{A3,B2},{B1,B2},10.
,1ںָ[7,8]ڵĻ¼
:{A1,A2},{A1,A3},{A2,A3},{A1,B1},{A1,B2},{A2,B1},{A2,B2},{A3,B1},{A3,B2},9.
ĸP=10.
9
.
ⷨ:ںָ[7,8]ڵġʡ̨ΪA1,A2,A3;ںָ[4,5)ڵġʡ̨ΪB1,B2.ںָ[4,5)[7,8]ڵġʡ̨ȡ2ҵеĻ¼
:{A1,A2},{A1,A3},{A2,A3},{A1,B1},{A1,B2},{A2,B1},{A2,B2},{A3,B1},{A3,B2},{B1,B2},10.
,û1ںָ[7,8]ڵĻ¼:{B1,B2},1. ĸP=1-10=10.
(2)20ҡʡ̨ںָƽ 4.5+5.5+6.5+7.5=6.05.
20202020
17.(2015Ĵ,17,12)һСͳ5λ,λΪ1,2,3,4,5.˿P1,P2,P3,P4,P5λŷֱΪ1,2,3,4,5,ǰλŴС˳Ⱥϳ.˿P1ԭûԼ1λ,ʱ˾Ҫµij˿Ͱ¹:Լλ,ֻԼλ;Լλг˿;,5λʣλѡλ.
(1)˿P13λ,˿Ͱ,ʱ4.±,(˿;λпո); (2)˿P12λ,˿Ͱ,˿P55λĸ.
˿ P1 3 3 λ P2 2 2 P3 1 4 P4 4 5 P5 5 1 2
8
7
3
1
9