Answer:
You are now 38 m below base camp.
Step-by-step explanation:
Consider the provided information.
You start hiking at an elevation that is 80 meters below base camp.
Now your initial location is 80 m below base camp, that can be represents as: -80
Now you increase your elevation by 42.
So you go up by 42.
In other words, you get the equation -80+42 = -38.
Since, a negative value is below the base camp, this means that you are now 38 m below base camp.