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?

Q. A submarine is at a depth of 500 meters below sea level. It dives deeper for 10 minutes at a rate of 20 meters per minute and then starts going up at a rate of 10 meters per minute. How long will the submarine take to reach the surface?

Q. A submarine moved from the water surface at a speed of $(-20)m$ per minute. How far is the submarine from the water surface at the end of $7$ minutes?

Q. A submarine descends from surface of the water at a speed of (30) m per minute. How far the submarine will be from the surface of water after 20 minutes? [ Take the descending distance as a negative integer]

Q. A submarine dives from the water surface at an angle of ${30}^0$ below the horizontal, following a straight path $50m$ long. How far is the submarine then below the water surface?

Q. A submarine is at sea level. At 8.00 p. m it begins to descend at a rate of 8 m per minute. At what time will it be at - 240 m ?