Step-by-step explanation: the scuba diver starts at sea level (0) then swims down 30 feet (-30). after a couple minutes, goes down 10 feet more (-40) the scuba diver will now be -40 down from sea level. so it should be -40 because the scuba diver swam that much down.
lmk if this is incorrect, i'm not quit sure if it is or not. if i'm wrong, i'm so sorry!!
