Question

A sumbrine moved from the water surface at a speed of (-20)m per minute.how far is the sumbrine from the water surface at the end of 7 minute

Answer 1

-20 × 7 = -140

Thus the submarine was 140 m below the surface of water.

Answer 2

a submarine move at the speed of -20m per minute that means it submerge 20m below sea in 1 min.
speed= -20m/min
time= 7 minutes.
distance= speed x time
distance = -20*7
              = -140m

distance submerged is -140 m.
so its 140 m below sea level. or 140m away from the water surface.