Question

A bag contains $18$ balls out of which $x$ balls are red.
If one ball is drawn at random from the bag, what is the probability that it is not red?

Answer 1

Total No . of Observations $=18$
Number of Red Balls $=x$
Probability of Red Ball $=$ Favourable Observations / Total No. of Observations

$P($ of Red Ball$)$= \dfrac{x}{18}$

$P($ not red ball $)=1-\frac{x}{18}$

$=\frac{(18-x)}{18}$.