Final answer:
Vario's elevation, in relation to the other scuba diver at -30 feet, is -10 feet.
Step-by-step explanation:
In this scenario, Vario, a scuba diver, starts at an elevation of -20 feet. He then descends 20 feet more, resulting in a total descent of 40 feet. The other person is diving at an elevation of -30 feet.
To find Vario's elevation in relation to the other diver, we need to calculate the relative elevation. Relative elevation is the difference between the elevations of two locations.
So, to find the relative elevation, we subtract the elevation of the other diver (-30 feet) from Vario's final elevation (which is -20 feet - 20 feet = -40 feet):
Relative elevation = Vario's elevation - Other diver's elevation = -40 ft - (-30 ft) = -40 ft + 30 ft = -10 ft
Therefore, Vario's elevation, in relation to the other diver at -30 feet, is -10 feet.