Question 1116293
.
<pre>
The correct equation is (and must be !) 


h(t) = -5t^2 + 60t.


To answer the question, you need to solve the equation  h(t) = 27,  which is the same as


-5t^2 + 60t = 27,


5t^2 - 60t + 27 = 0.


Solve it using the quadratic formula.


You will get two real positive roots.


One root is the time for  h(t) = 27 m  flying up;  the other root is the time for  h(t) = 27 m  falling down.



{{{graph( 330, 330, -3.5, 20.5, -20.5, 200.5,
          -5x^2 + 60x, 27
)}}}


Plot h(t) = -5t^2 + 60t (red) and y = 27 (green)
</pre>