A bag contains a black ball, a red ball and a green ball, all the balls are identical in shape and size. A ball is drawn from the bag without looking into it. What is the probability that the ball drawn is:
Not a red ball
$${\textbf{Step-1: Find probability for a not red ball.}}$$
$${\text{Red ball =1, Black ball=1, Green ball=1.}}$$
$${\text{Total balls in bag=3.}}$$
$${\text{Let P be the probability of getting a not red ball.}}$$
$$\text{Probability=}\dfrac{\text{No. of outcomes(Black and Green)}}{\text{Total no. of outcomes}}$$
$$\text{Probability=}\dfrac{2}{3}$$
$${\textbf{Hence, probability of getting red ball is}}$$ $${\mathbf{\dfrac{2}{3}.}}$$