Let the set A is {1, 2, 3} and B is {2, 3, 4}. Then the number of elements in A U B is?
(a) 4
(b) 5
(c) 6
(d) 7
The question was posed to me in semester exam.
I need to ask this question from Set Operations topic in portion Basic Structures: Sets, Functions, Sequences, Sums and Matrices of Discrete Mathematics