A= {a,b,c} . Since this set has 3 elements, the number
of its total subset is 2³ = 8 (including the Ф element):
Here below all the subsets of {a,b,c}, with their related probabilities, knowing that P(a) = 1/2 ; P(b) = 1/3 and P(c) = 1/6
{a} →→→→1/2
{b} →→→→1/3
{c} →→→→1/6
{a,b} →→→→1/2 + 1/3 = 5/6
{a,c} →→→→1/2 + 1/6 = 2/3
{b,c} →→→→1/3 + 1/6 = 1/2
{a,b,c} →→→→1/2 + 1/3 + 1/6 = 1
{∅} →→→→0 =0
