Question -
Answer -
Given: A bagcontaining 7 white, 5 black and 4 red balls.
By using the formula,
P (E) = favourableoutcomes / total possible outcomes
Two balls are drawn atrandom, therefore
Total possibleoutcomes are 16C2
n (S) = 120
(i) Let E be theevent of getting both white balls
E = {(W) (W)}
n (E) = 7C2 =21
P (E) = n (E) / n (S)
= 21 / 120
= 7/40
(ii) Let E be theevent of getting one black and one red ball
E = {(B) (R)}
n (E) = 5C14C1 =20
P (E) = n (E) / n (S)
= 20 / 120
= 1/6
(iii) Let E be theevent of getting both balls of same colour
E = {(B) (B)} or {(W)(W)} or {(R) (R)}
n (E) = 7C2+5C2+4C2 =37
P (E) = n (E) / n (S)
= 37 / 120