Final answer:
The appropriate dose of activated charcoal for a 20-kg child is not provided in the given information. A healthcare provider must determine the correct dose based on specific circumstances, which typically ranges from 25 to 50 grams.
Step-by-step explanation:
The appropriate dose of activated charcoal for a 20-kg child is not clearly provided in the information given. The information provided relates to x-ray absorption and BMI, which are not relevant to determining a dose of activated charcoal. Activated charcoal dosing usually depends on the type of ingestion and the weight of the individual, and for children, it can typically range from 25 to 50 grams as a single dose.
It's important for a healthcare provider to determine the correct dose based on the specific circumstances.