Solution:Given that a box contains 3 blue, 2 white, and 4 red marbles.
We need to find the probability that if a marble is drawn at random, it is a red marble.
Probability of an event E is defined as:
There are 3 blue, 2 white, and 4 red marbles in the box, therefore, total number of marbles are:
Hence, the total number of possible outcomes is 9.
There are 4 red marbles, therefore, the number of favorable outcomes is 4.
Let be the event that a red marble is drawn.
Now, the probability of getting a red marble is,
The probability of getting a red marble is .
Therefore, option 4 is correct.