Question 1145768
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<pre>

This moment " t " is the root of the equation  H(t) = 0,  which is


    -16*t^2 - 11t + 205 = 0,


or, equivalently,


     16t^2 + 11t - 205 = 0.


Solve this quadratic equation using the quadratic formula.

Choose the positive root.  It will be your answer.
</pre>

Having my instructions, you do the rest.


If you still have questions or problems with it, then let me know.