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 .dt tt 49 10 1200 2=- ++^h , where d represents the distance above the water, in metres, and t is the time, in seconds.

How long has the package been in the air when it hits the water?