Question

# If A = {1, 3, 5, 7, 9} and B = {2, 3, 5, 7}, what is ${\text{A}} \cup {\text{B}}$?A. {3,5,7}B. {2,3,5,7}C. {2,3,5,7,9}D. {1,2,3,5,7,9}

We need to find ${\text{A}} \cup {\text{B}}$.
So, ${\text{A}} \cup {\text{B}}$= {1, 2, 3, 5, 7, 9}.
Note: Whenever you face such types of problems with sets you need to know that U denotes union of sets and $\cap$ denotes intersection of sets. The union (denoted by ∪) of a collection of sets is the set of all elements in the collection. From this information we will get the right solution to this question.