Question 1195640
n=number and there are 10 elements in A, and there are 10 elements on n(-A).
There are 9 elements in B.
The intersection is {1,10,16,17}
The union is {1,2,3,4,5,6,7,9,10,12,13,15,16,17,18}
There are 19 elements in both combined, 4 are the same, that leaves 15 in the union which are shown above.