SOLUTION: The possibility space consists of the integers from 1 to 20 inclusive. A is the event ' the number is a multiple of 3'. B is the event 'the number is a multiple of 4'. An intege

That means the universal set U is all the integers from 1 through 20.
U = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20}

That means A is the set of integers of U you get by counting by 3's.
A = {3,6,9,12,15,18}

That means B' is the set of integers of U you get by counting by 4's.
B = {4,8,12,16,20}
B' = set of elements of U that are not in B ={1,2,3,5,6,7,9,10,11,13,14,15,17,18,19}




Count those numbers of elements and make those fractions.  Reduce the fractions if
possible.

Edwin