Question

Let A1 = { 1 , 2 , 3 , 4 , 5 , 6 }, A2 = { 7 , 8 , 9 , 10 , 11 , 12 , 13 } and A3 = { 14 , 15 , 16 , 17 , 18 , 19 }.

How many non-empty sets are there which are a subset of A1 OR a subset of A2 Or a subset of A3?

Answer 1

a set of n elements has 2^ⁿ-1 non-empty subsets