Question

Jika dadi dilambungkan 2 kali dan mata dadu yang terlihat dijumlahkan peluang junlah mata dadu kurang dari 7 atau bilangan prima adlah?

Answer 1

Misalkan,
A = kejadian muncul mata dadu berjumlah kurang dari 7 = { (1,1) (1, 2) (1,3) (1,4) (1, 5) (2,1) (2, 2) ( 2, 3) (2, 4) (, 3, 1) (3, 2) (3, 3) (4,1) (4, 2) (5, 1)}
n(A) = 15

B = Kejadian muncul mata dadu berjumlah bilangan prima = {(1, 1) (1, 2) (1, 4) (1, 6) (2,1) (2, 3) (2, 5) (3, 2) (3, 4) (4, 1) (4, 3) (5, 2) (5, 6) (6, 1) (6, 5)}
n(B) = 15

(A ∧ B) = {(1, 1) (1, 2) (1, 4) (2, 1) (2, 3) (3, 2) (4, 1)}
n(A ∧ B) = 7

n(S) = 36

P(A atau B) = P(A ∨ B) = P(A) + P(B) - P(A ∧ B)
                   = 15/ 36 + 15/ 36 - 7/36
                   = 23/36