PLIS BANTU DONG! 1. Dua buah dadu dilempar bersama, frekuensi harapan muncul mata dadu berjumlah kurang dari 9 adalah 65. Banyak pelemparan dalam percobaan itu

1.
Dua buah dadu
S={(1,1)(1,2)(1,3)(1,4)(1,5)(1,6)(2,1)(2,2)(2,3)(2,4)(2,5)(2,6)(3,1)(3,2)(3,3)(3,4)(3,5)(3,6)(4,1)(4,2)(4,3)(4,4)(4,5)(4,6)(5,1)(5,2)(5,3)(5,4)(5,5)(5,6)(6,1)(6,2)(6,3)(6,4)(6,5)(6,6)}
n(S)=36
A=peluang muncul mata dadu berjumah kurang dari 9
A={(1,1)(1,2)(1,3)(1,4)(1,5)(1,6)(2,1)(2,2)(2,3)(2,4)(2,5)(2,6)(3,1)(3,2)(3,3)(3,4)(3,5)(4,1)(4,2)(4,3)(4,4)(5,1)(5,2)(5,3)(6,1)(6,2)}
n(A)=26
P(A)=n(A)/n(S)
=26/36
=13/18

frekuensi harapan A=n×P(A)
65=n×13/18
65×18/13=n
90=n
n=90 kali

2.
4 mata uang logam
S={AAAA,AAAG,AAGA,AAGG,AGAA,AGAG,AGGA,AGGG,GAAA,GAAG,GAGA,GAGG,GGAA,GGAG,GGGA,GGGG}
n(S)=16
A=peluang muncul paling sedikit 2 angka
A={AAAA,AAAG,AAGA,AAGG,AGAA,AGAG,AGGA,GAAA,GAAG,GAGA,GGAA}
n(A)=11
P(A)=n(A)/n(S)
=11/16

Semoga bisa membantu...