Quadratic functions

Question

on the reality tv show last man standing a package is thrown from a plane to the ocean below. the contestants must swim to the package to receive the free pass located inside the package. the path that the package follows can be modelled by the quadratic function d(t) = -4.9t^2 + 10t +1200 where d represents the distance in meters that the package travels and t is the time in seconds. How long will it take for the package to reach the water?

Answer 1

The function d(t) is the height of the package above the water, assuming it was tossed straight up from 1200 meters at a speed of 10 m/s.

 

Set d(t) = 0 and solve for t using the quadratic formula.  You will get a positive and a negative solution.  Since time starts at t = 0, discard the negative solution.  The positive solution is the correct answer.