Half-life is time period in which the quantity of an entity is reduced to half of its primary value. In modern physics, the description of exponential and non-exponential decay of substance overtime is called radioactive decay.

When there is a decay of same number of atoms but kept in multiple places, the decay follow the probability theorem of LLN or Law of Large Numbers, this theorem states that when a same experiment is performed multiple times the results tends to approach closer to the average of all the results combined. Therefore, every container will have number of atoms closer to the value 5000. Therefore, due to LLN, the containers will in general have different numbers of the atoms of the material but their average will be close to 5000.