Explanation:
6. Let C = {multiples of 3} and D = {30, 60, 90}.
a. Explain why D ⊂ C.
Answer: Every element of D is in C though C has more elements. Elements which are in D are all multiples of 3. So they both make a proper subset.
b. Let set E = {1, 3, 6, 9, 12}. Explain whether E ⊂ C.
Answer: No, as 1 is not a multiple of 3. So it does not fall under the set C making it a proper subset to set E.
