Kelly has 2 boxes containing a total of three rings. The larger box has three rings in it and the smaller box has one ring in it. If she only has three rings altogether how is that possible?

The small box is also in the large box.

Step-by-step explanation:

This concept involves the idea of sets. There are total of 2 boxes (2 sets) and 3 rings (3 elements). However, the smaller box contains one ring and the bigger box contains 3 rings. This is only possible if the small box is also in the large box. This is the concept of subset, in which one set has all the elements of the other set but the elements of the latter set do not lie on the former set. It can be implied that the smaller box is the subset of the larger box. The larger box contains one ring which lies in the small box and 2 rings which do not lie in the small box. Therefore, the situation is possible if and only if the small box is the subset of the large box that is the former lies within the latter!