Answer:
The rate of change in the submarine's elevation is 26.0 feet per second.
Explanation:
She begins 151 feet below sea level
Thus, her initial point is y₁ = 151 feet below sea level
i.e. at t₁=0 seconds, y₁ = 151 feet below sea level
After descending for the 3 seconds, she is 229 feet below sea level.
Thus, her second point is y₂ = 229 feet below sea level after 3 seconds
i.e. at t₂=3 seconds, y₂ = 229 feet below sea level
The rate of change is basically the slope. Thus, the rate of change can be obtained by taking the slope.
slope = rate of change = (y₂ - y₁)/(t₂ - t₁)
= (229 - 151) / (3 - 0)
= 78/3
= 26.0
Therefore, the rate of change in the submarine's elevation is 26.0 feet per second.