She going down, the value is negative. When going up, the value is positive. So when the swimmer swims down 300 feet, the value is negative. Then he goes up 150 ft, which makes the value positive. Finally, he swims down 50 ft, so the valued is negative.
Step-by-step explanation: If a swimmer is diving down that takes him below ground level which is why he'd be going negative. therefore your answer would be -300 + 150 + (-50).
