SOLUTION: Let S be the universal set, where: S={1,2,3,...,18,19,20} Let sets A and B be subsets of S, where: Set A={2,3,7,12,15,16,18} Set B={1,2,3,5,7,9,10,11,17} Find the followi

Algebra ->  Finite-and-infinite-sets -> SOLUTION: Let S be the universal set, where: S={1,2,3,...,18,19,20} Let sets A and B be subsets of S, where: Set A={2,3,7,12,15,16,18} Set B={1,2,3,5,7,9,10,11,17} Find the followi      Log On


   



Question 1047211: Let S be the universal set, where: S={1,2,3,...,18,19,20}
Let sets A and B be subsets of S, where:
Set A={2,3,7,12,15,16,18}
Set B={1,2,3,5,7,9,10,11,17}
Find the following:
The number of elements in the set (A∪B): n(A∪B) =
The number of elements in the set (A∩B): n(A∩B) is

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
AUB is the set of elements of S that are part of A or B, or both.
A∪B = {1,2,3,5,7,9,10,11,12,15,16,17,18}
I could count them, but there are too many, and I have not had my first cup of coffee yet.
A∪B is all of S except 4, 6, 8, 13, 14, 19, and 20.
S had 20 elements, and 7 were left out, so
n(A∪B) = 20-7 = highlight%2813%29 .
A∩B is the set of elements of S that are common to A and B.
A∩B = {2,3,7} , so n(A∩B) = highlight%283%29 .