Answer:
You can deduce that the child is under 8 years old, but older than 5 years old
Explanation:
The question states that there is a sign saying that no one under 5 is allowed inside. Because we know that the child is indeed inside the house, he must be older than 5. The question also states that the child is with his parents. We know that there is a second sign saying that no on under 8 is allowed without a parent. This lets us know that the child must be under 8, as he is with his parents in the house. Therefore you can deduce that the child is under 8 years old, but older than 5 years old.