Final answer:
A set of Russian nesting dolls, also known as matryoshka dolls, consists of multiple dolls nested inside each other. The number of dolls in the set corresponds to the number of layers or levels. The set can have an infinite number of dolls as the size decreases at each level.
Step-by-step explanation:
A set of Russian nesting dolls, also known as matryoshka dolls, consists of multiple dolls nested inside each other. To determine the different possible numbers of dolls in a set, we need to count the number of layers or levels of nesting. In a set with an outermost doll of width 20cm, the number of dolls in the set corresponds to the number of layers or levels. Each layer nested inside the previous one decreases in size by a certain proportion, typically around 0.75. Let's calculate the different possible numbers of dolls: Level 1: 1 doll (outermost doll), Level 2: 1 doll nested inside the outermost doll, Level 3: 1 doll nested inside level 2 doll, And so on...Therefore, the set can have infinite dolls as the size decreases in each level, resulting in an infinite number of layers or levels.