SOLUTION
We want to find the probability of picking a number that is "not an odd number" out of the numbers 2, 3 and 4.
Now, the total numbers are three.
Not odd numbers, means the numbers are even. The even numbers here are 2 and 4, that is two numbers.
Probability is calculated as
The number of possible outcome here is "not odd numbers", that is even numbers which is 2.
The total outcome is the three numbers, which is 3.
Hence the required probability becomes
Hence the answer is