Question

Exercitiul 31 va rooog!!

Answer 1

P de aceeasi culoare=P albe+P rosii
In cate feluri pot extrage 3 bikle albe din 4 bile albe? In comb de 4 luate cate 3
In cate feluri pot extrage 0 bile rosii din 6 bile rosii?
In comb de 6 luatecatr 0
Aceste evenimente sunt independente deci pt cazuri favorabile vom inmulti aceste numre
cazuri posibile: in cate feluri pot fi extrase 3 v bile oarecare din 6=4=10 bile? In Comb de 10 luatecate 3
Atunci


P albe =(Cmb de4 luate cate 3* Combde 6 luatecate 0)/Combinaride 10 luate cate 3=
4*1/120=1/30
ptca Coombde 10 luate cate 3= 10!/7!*3!=8*9*10/2*3=4*3*10=120

Prosii=Comb de 6 luate cate 3*Comb 4 luate cate0/Combinaride 10luate cate3

Comb de 6 luatecate 3=20
Prosii=20*1/120=1/6

ptca Comb de 6 luate cate3= 6!/3!*3!=485*6/2*3=4*5=20

Probabilitate totala= Palbe +P rosii=
1/30+1/6=1/30+5/30=6/30=1/5=20%