Given the sets A = multiples of 3 less than 12, B = integers between 4 and 8, and C = 4, 5, 7, find A intersection B and A union B.

Here are the solutions to the questions:

1. (a)
Given the sets:
$A = \{\text{multiples of 3 less than 12}\} = \{3, 6, 9\}$
$B = \{\text{integers between 4 and 8}\} = \{5, 6, 7\}$
$C = \{4, 5, 7\}$

• (i) Find $A \cap B$: This is the set of elements common to both A and B. $A \cap B = \{6\}$ The intersection is $\boxed{\{6\}}$.

• (ii) Find $(A \cup B) \