Final answer:
There are 144 different ways to seat four adults and four children at a circular table, with the constraint that each child must be next to another child.
Step-by-step explanation:
To determine how many different ways four adults and four children can be seated at a circular table with the condition that every child must be seated next to another child, consider the restriction as a single unit. This reduces the problem to arranging five units (four single adults and one unit of four children) in a circle. Since rotations of the same arrangement are considered identical in circular permutations, we effectively have one less unit to arrange. Thus, we arrange (5-1) units or 4 units in a straight line, which corresponds to (4-1)! permutations. Now, the four children can be arranged among themselves in 4! ways. Therefore, the total number of possible arrangements is 3! × 4!, which equals 6 × 24, or 144 different ways they can be seated.