Final answer:
The speed of the waves in the lake is calculated by dividing the wavelength (6 meters) by the time interval (2 seconds), resulting in a wave speed of 3 m/s.
Step-by-step explanation:
The speed of waves is calculated by dividing the wavelength by the time it takes for a wave to pass a given point. In the provided question, the waves in a lake are 6 meters apart (which is the wavelength) and they pass the person on a raft every 2 seconds. Using the formula for wave speed (speed = wavelength / time), the speed of the waves is calculated as follows: speed = 6 meters / 2 seconds = 3 m/s.