Answer:
7.5 m above sea level
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Explanation:
We are given:
The elevation of Homer = -30 feet [30 feet below sea level]
The elevation of Marge = +45 feet [45 feet above sea level]
The elevation of Bart is at the exact mid-point of the elevations of Homer and Marge
The elevation of Bart:
We are given that the elevation of Bart is at the exact mid-point of the elevations of Homer and Marge
So, Half the distance between the elevation of Homer and Marge is the elevation of Bart
Elevation of Bart (with respect to the elevation of Homer) =
(elevation of Marge - Elevation of Homer) / 2
replacing the variables with the suitable values:
(+45 - (-30))/2
(45 + 30) / 2
75 / 2
Elevation of Bart (w.r.t. Homer) = 37.5 feet
Since this is the elevation of Bart with respect to Homer, we can say that Bart is 37.5 m above Homer
So, we can say that:
Elevation of Bart (w.r.t Homer) = Elevation of Bart - Elevation of Homer
replacing the values
37.5 = Elevation of Bart -(-30)
37.5 = Elevation of Bart + 30
Elevation of Bart = 7.5 m above sea level [subtracting 30 from both sides]