Question

A submarine left the surface of water at the rate of $-6\mathrm{feet}$per second. At that rate, how long, would the submarine take to reach $-180\mathrm{feet}$level?

Answer 1

Problem on integers:

Time taken by a submarine for $-6\mathrm{feet}=1\sec$

Time taken by a submarine for $-1\mathrm{feet}=\frac{-1}{6}\sec$

Time taken by a submarine for $-180\mathrm{feet}=\frac{-1}{6}\times -180=30\sec$

Hence, the submarine would take $30\mathrm{seconds}$ to reach $-180\mathrm{feet}$ level.