A box contains 5 black and 4 white balls. A ball is drawn at random and its colour is noted. The ball is then put back in the box along with two additional balls of its opposite colour. If a ball is drawn again from the box, then the probability? that the ball drawn now is black, is :
- $\frac{5}{11}$
- $\frac{53}{99}$
- $\frac{48}{99}$
- $\frac{7}{11}$
The Correct Option is C
Solution and Explanation
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Concepts Used:
Random Experiments
An Experiment is the activity that produces a result or an outcome. It is an element of uncertainty as to which it occurs when we perform an activity or experiment. Normally we get a different number of outcomes from an experiment. However, when an experiment satisfies the following two conditions, it is known as random experiment.
- It has more than one possible outcome.
- It is not possible to predict the outcome in advance.
On the basis of random experiment we can identify whether the given experiment is random or not. Let’s check with the help of example which is a random experiment and which is not.
Question: Using a calculator, divide 36 by 4. Now check, whether it is a random experiment or not.
Solution:
- This activity can be repeated under identical conditions though it has only one possible result.
- The outcome is always 9, which means we can predict the outcome each time we repeat the operation.
The given activity is not a random experiment.