Use the given ratios and the fact that children = boys + girls to find the required ratio.

• Girls : Total = \(1 : 11\), so girls = 1 part, total = 11 parts
• Children : Adults = \(3 : 8\), so children = 3 parts, adults = 8 parts
• Boys = children − girls = \(3 - 1 = 2\) parts
• Children : Adults = \(3 : 8\)

Final Answer: 3 : 8