Solution:Goods can also be non-excludable but rivalrous, which means that everyone can access them. Still, their consumption can affect the overall supply and the units left for other consumers to use.
For e.g., students in a dormitory experiencing poor water supply can use tap water for bathing and other purpose anytime.
An example for this is 'a fish in the ocean'. It is rivalrous in consumption because if one person catches the fish.
However, it is non-excludable because its nearly impossible to prevent people from fishing in the open sea.