Final answer:
The normal speed limit in a school zone when children are present is around 20 mph or 30 km/h to ensure their safety.
Step-by-step explanation:
The normal speed limit in a school zone when children are present is usually lower than the regular speed limit to ensure the safety of the children. In many places, the speed limit is typically around 20 miles per hour (mph) or 30 kilometers per hour (km/h) in school zones. It is important to be cautious and follow the posted speed limit signs to prevent accidents and ensure the well-being of the students.