Answer: Option A
:
A
Given,
Number of green balls = 5
Number of black balls = 6
Number of white balls = 7
Total numberof outcomes = 5 + 6+ 7 = 18
There are 18 balls out of which 11 are not white.
$\Rightarrow$ Number of favourable outcomes = 11
$\text{Probability of an event, P(E)}=\frac{\text{Number of favourable outcomes}}{\text{Total number of outcomes}}$
$\Rightarrow$ P(balldrawn isnotwhite) = $\frac{11}{18}$
$\therefore$ Probability that the ball drawn is not white is $\frac{11}{18}$ .
Alternate Method:
P (balldrawn is white) = $\frac{7}{18}$
By complementary event formula,
P( balldrawn is white) +P( balldrawn is not white) = 1
$\Rightarrow$ P( balldrawn is not white)
$=1-\text{P( balldrawn is white)}$
$=1-\frac{7}{18}=\frac{11}{18}$
$\therefore$ Probability that the balldrawn is not white is $\frac{11}{18}$.