From - 12 surface sea level, a submarine descends 20 feet per minute. Where is the submarine in relation to sea level 7 minutes after it starts descending?

-152 feet in relation to sea level.

Step-by-step explanation:

If it descends 20 feet per minute, you just multiply the distance by the minutes. So 20x7 and you will get 140. You can't forget that it's already -12 below sea level, so it's 12 feet deeper. It's -152 feet in relation to sea level.

v: l•w•h÷2.

v: 20•6•8 ÷2

v: 960÷2

v: 480