Answer:
New position = -525 ft or 525 ft below the sea level
Step-by-step explanation:
Lets h be the height of the sea.
Given:
A submarine was situated 800 feet below sea level.
It is ascends 275 feet.
We know that h = 0 on the surface of the sea.
When we go below the surface vertically inside the sea the height will become negative.
So the submarine was situated h = -800 feet below the sea level, and it is ascends 275 feet from -800 feet.
So the new height of the submarine is.


Therefore the new position of the submarine is 525 below the sea level.
Answer:
D. 21/2
Step-by-step explanation:
We simply have to evaluate the first three terms based on the progression's formula:
t= 1, the first term is 8, as we see:

t=2, the second term is 2, as we see:

t=3, the third term is 1/2, as we see:

The sum of the first 3 terms is then: 8 + 2 + 1/2 = 10 1/2
Among the answer choices, D. 21/2, which is 10 1/2.
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