If C = { 2, 4, 6, 8, 10, 12, 14, 16 }, and D = {5, 10, 15, 20}, then the number of elements in the set D - C is:
3
D - C represents the elements in set D that are not in set C. D = {5, 10, 15, 20} C = {2, 4, 6, 8, 10, 12, 14, 16} Elements in D that are not in C: {5, 15, 20} Thus, the number of elements in D - C is 3.
Important Questions from Operations on Sets
If $A, B, C$ be three sets such that $A \Delta B = A \Delta C$ and $A \cap B = A \cap C$, then,
Match List I with List II
Let R 1= {(1, 1), (2, 2), (3, 3)} and R 2 = {(1, 1), (1, 2), (1, 3), (1, 4)}
List I
List II
(A) R 1∪ R 2
(I) {(1, 1), (1, 2), (1, 3), (1, 4), (2, 2), (3, 3)}
(B) R 1- R 2
(II) {1, 1}
(C) R 1∩ R 2
(III) {(1, 2), (1, 3), (1, 4)}
(D) R 2- R 1
(IV) {(2, 2), (3, 3)}
Choose the correct answer from the options given below:
For any two sets A and B, A - (A - B) equals
Let R be a relation on a set A such that R = R-1, then R is
Which of the following is an open set?
