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:
a white ball

Answer

To solve the problem step by step, we will determine the probability of drawing a white ball from a bag that contains a black ball, a red ball, and a green ball.

### Step-by-Step Solution:

1. **Identify the Total Number of Balls**:
- The bag contains three balls: one black ball, one red ball, and one green ball.
- Therefore, the total number of balls in the bag = 3.

2. **Identify the Favorable Outcomes**:
- We need to find the probability of drawing a white ball.
- However, we can see that there are no white balls in the bag. The balls present are black, red, and green only.

3. **Calculate the Probability**:
- The probability of an event is given by the formula:
\[ \text{Probability} = \frac{\text{Number of Favorable Outcomes}}{\text{Total Number of Outcomes}} \]
- In this case, the number of favorable outcomes (drawing a white ball) = 0 (since there are no white balls).
- Therefore, the probability of drawing a white ball is:
\[ \text{Probability of drawing a white ball} = \frac{0}{3} = 0 \]

4. **Conclusion**:
- The probability that the ball drawn is a white ball is 0.

### Final Answer:
The probability that the ball drawn is a white ball is **0**.