A submarine is 400 feet below seal level if the submarine rise by 100 feet what is his elevation

The submarine will be 300 feet below sea level.

Step-by-step explanation:

If a submarine rises while underwater, then the feet below sea level will decrease.

So the submarine is at 400 feet below sea level, and if it rises 100 feat, then it will be x feet below sea level.

Lets put this into an equation: 400 - 100 = x

Now solve for the equation:

400 - 100 = x

x = 300

The submarine will be 300 feet below sea level.