Given data:
The given rate of the submarine is r=7 feet per second.
The given time is t=30 seconds.
The given expression for the distance is,
[tex]d=r\times t[/tex]Substitute the given values in the above expression.
[tex]\begin{gathered} d=(7\text{ ft/s)(30 s)} \\ =210\text{ ft} \end{gathered}[/tex]Thus, the altitude is 210 feet.
