Sets
4 marks · NormalThe sets and are shown.
Write down .
Write down .
List all elements of the set (the complement of ), assuming the universal set is .
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) {2, 3}
(b) {1, 2, 3, 4, 5, 7}
(c) {5, 6, 7}
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correct intersection elements {2, 3} only.
B1 (b) · 1 mark · Correct union elements {1,2,3,4,5,7} only.
B1 (c) · 2 marks · Correct complement elements {5,6,7}; all present and only these.
Worked solution
(a) The intersection is the elements in both B and C: 2 and 3.
(b) The union is all elements in either B or C: 1, 2, 3, 4, 5, 7.
(c) The complement of C (in the universal set \{1,2,3,4,5,6,7\}) is those not in C: 5, 6, and 7.