The girl traveled 120 kilometers in 3 hours at a speed of 40 km/h.
Speed is defined as the magnitude of an object's rate of change in position over time. It is a scalar quantity, which means it has simply magnitude and no direction.
It is calculated by dividing the distance traveled by the time required:
Distance x Time = Speed
We calculate the distance the girl traveled by using the formula:
Distance = Speed x Time
Distance (D) = unknown
Speed (S) = 40 kilometers per hour (km/h)
Time (T) = 3 hours
Plugging these values into the formula, we get:
D = 40 km/h x 3 hours
D = 120 kilometers