Answer:
128
Step-by-step explanation:
Each of the 7 elements of the set can be included in a subset, or not. That gives 2 possibilities for each of those elements.
Subset count
The count of subsets of an n-element set is thus 2^n. So, for this 7-element set, the possible number of subsets is 2^7 = 128.
This includes the empty set { } and the full set {7, 20, 28, 31, 49, 56, 63}.
