given: bag which contains 8 red and 5 white balls

formula:

total number of ways of drawing three balls at random is ¹³C₃

therefore n(S)=286

(i) let E be the event of getting all white balls

E= {(W) (W) (W)}

n(E)= ⁵C₃=10

(ii) let E be the event of getting all red balls

E= {(R) (R) (R)}

n(E)= ⁸C₃=56

(iii) let E be the event of getting one red and two white balls

n(E)= ⁸C₁⁵C₂=80