The expression -320+15y represents a submarine that began at a depth of 15 feet below sea level and ascended at a rate of feet per minute. What was the depth of the submarine after 15 minutes?

Step-by-step explanation:

Given an expression that represents a submarine that began at a depth of 15 feet below sea level and ascended at a rate of feet per minute is as follows :

-320+15y

We need to find the depth of submarine after 15 minutes.

Put y = 15 in the above expression.

-320+15y = -320+15(15)

= -320 + 225

= -95

Hence, the submarine is below sea level at 95 feet.