+314 The equation $y = -16t^2 - 60t + 54$ describes the height (in feet) of a ball thrown downward at 60 feet per second from a height of 54 feet from the ground, where $t$ represents time, measured in seconds. In how many seconds will the ball hit the ground? Express your answer as a decimal rounded to the nearest hundredth.
+314 Setting $y$ to zero, we get the quadratic −16t2−60t+54=0.Dividing both sides by $-2,$ we get 8t2+30t−27=0.This quadratic factors as $(4t - 3)(2t + 9) = 0.$ As $t$ must be positive, we can see that $t = \frac{3}{4} = \boxed{0.75}.$ 
