Final answer:
The girl's displacement is 500 meters to the west, calculated by subtracting the distance traveled back towards home from the original distance from her house.
Step-by-step explanation:
The student's question involves calculating displacement, which is a vector quantity that represents the change in position of an object. In this scenario, the girl rides her bike 1600 m west from her house, and then rides back 1100 m. To calculate her displacement, we subtract the distance she traveled back (1100 m) from the original distance (1600 m). Displacement is directional, so if west is considered the negative direction, her displacement would be -1600 m + 1100 m = -500 m. Hence, the girl's displacement is 500 m to the west.