Answer:
The scientist spent 450 seconds in descending after boarding the submarine.
Step-by-step explanation:
The ocean floor directly beneath the boat is at a depth of 180 meters.
The submarine descends at a constant rate of 0.4 meters per second.
So, to reach 180 meters time taken will be = [tex]\frac{180}{0.4}= 450[/tex] seconds
Therefore, the scientist spent 450 seconds in descending after boarding the submarine.
