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.
