22. A ball is thrown into the air with an upward velocity of 24 ft/s. Its height (h) in feet after t seconds is given by the function h = –16t2 + 24t + 5. How long does it take the ball to reach its maximum height? What is the ball’s maximum height? Round to the nearest hundredth, if necessary. (1 point)
a. 1.5 s; 5 ft.
b. 0.75 s; 32 ft.
c. 0.75 s; 11 ft.
d. 0.75 s; 14 ft.

Question

22.	A ball is thrown into the air with an upward velocity of 24 ft/s. Its height (h) in feet after t seconds is given by the function h = –16t2 + 24t + 5. How long does it take the ball to reach its maximum height? What is the ball’s maximum height? Round to the nearest hundredth, if necessary. (1 point)
a.	1.5 s; 5 ft.
b.	0.75 s; 32 ft.
c.	0.75 s; 11 ft.
d.	0.75 s; 14 ft.

anonymous · Answer

$$h = –16t^2 + 24t + 5$$ is the equation for a parabola.  the vertex of the parabola always has the first coordinate $-\frac{b}{2a}$ which in  your case is \(-\frac{24}{2\times (-16)}=\frac{3}{4}\]

anonymous · Answer

i means 
 which in your case is $-\frac{24}{2\times (-16)}=\frac{3}{4}$

anonymous · Answer

replace $t$ by $\frac{3}{4}=.75$ to find the height