A bag contains `5` white , `7` red and `8` black balls . If four balls are drawn one by one with replacement, what is the probability that :
(i) all are white ?
(ii) only `3` are white ?
(iii) none is white ?
(iv) at least three are white ?

Answer

(i) `((1)/(4))^(4)`
(ii) `4C_(3)((1)/(4))^(3)((3)/(4))^(4-3)`
(iii) `((3)/(4))^(4)`
(iv) `13((1)/(4))^(4)`