A seal dives below the ice in search of fish. Its path can be modelled by  where d is the depth in decameters and t the time in minutes. Use the equation above to answer questions about the seal's journey into the deep sea with an initial velocity of 24 decameters per minute. Use the graph below  to answer the question. 

Find the time it takes to reach the bottom of its trajectory. - no calculus can be used.

 

-0.5 depth (dam) -10 12 14 -16 -18 20 time (min) 4,0 0,5 10 15 2,0 25 3.5