a stream flows with a speed of 3.0 meters per second relative to the shore. A kayaker paddles Downstream with the speed of 1.5 meters per second relative to the stream. What is the kayaker speed relative to the shore

Since the kayakers speed is 1.5 meters per second relative to the stream, the kayakers velocity in meters per second relative to the shore should be its speed relative to the stream plus the stream's velocity relative to the shore. This is 1.5m/s + 3.0m/s which is equal to 4.5 meters per second (m/s).