Question

If A = {1, 2, 3, 4, 5} and B={4, 5, 6, 7} then A-B=__

• A. {1,2,3}
• B. {3,4,5}
• C. {5,6,7}
• D. {2,3,4}

Answer 1

The Correct Option is A

Step 1: Understand the operation \( A - B \)

\( A - B \) means the set of elements that are in \( A \) but not in \( B \).

Step 2: List the elements of sets \( A \) and \( B \)

\( A = \{1, 2, 3, 4, 5\} \)

\( B = \{4, 5, 6, 7\} \)

Step 3: Remove all elements of \( B \) from \( A \)

Elements common to both \( A \) and \( B \) are: \( 4 \) and \( 5 \)

So, remove 4 and 5 from set \( A \)

\[ A - B = \{1, 2, 3\} \]

Thus, the result is \( \{1, 2, 3\} \)

The correct option is (A): {1,2,3}