According to the question, a bag contains 8 red and 5 white balls.
By using the formula of probability, we get,
P (E) = favourable outcomes / total possible outcomes
Total number of ways of drawing three balls at random is ${ }^{13} \mathrm{C}_{3}$
n (S) = 286
(i) Let E be the event of getting all white balls
E= {(W) (W) (W)}
$n(E)={}^5C_3=10$
P (E) = n (E) / n (S)
= 10 / 286
= 5/143
(ii) Let E be the event of getting all red balls
E = {(R) (R) (R)}
$n(E)={}^8C_3=56$
P (E) = n (E) / n (S)
= 56 / 286
= 28/143