Problem Solving

What is the probability of selecting a clean number from a set of integers containing all multiples of 3 between 1 and 99, inclusive?

1. A clean number is an integer divisible by only 2 factors, one of which is greater than 2.
2. A clean number must be odd.

Source : Veritas

I am not sure why the OA is A. Knowing that there are a finite number of odd integers between 1 and 99, B should be sufficient...

They are really saying that a prime number, and just being odd does not make it a prime number.

I agree that the question seems a little misleading.

B is not sufficient because it doesn't give a concrete definition of what a clean number is. it gives one parameter - that it must be odd. But it doesn't define what a clean number is.

Statement A defines what a clean number is - an integer divisible by only 2 factors, one of which is greater than 2.