Answer:
The ring is probably not geniune.
Explanation:
To solve this problem we first need to calculate the density of the ring:
The mass is given by the problem, and we're able to assess the volume by keeping in mind Archimede's principle (the volume of water displaced by an object is equal to the object's volume).
Given that the ring density is significantly lower than the density of pure platinum, the ring is probably not geniune.