Anyone please help me on this??

A catapult launches a boulder with an upward velocity of 112 ft/s. The height of the boulder, h, in feet after t seconds is given by the function h= -16t squared + 112t + 30 .
How long does it take the boulder to reach its maximum height? What is the boulder’s maximum height? Round to the nearest hundredth, if necessary.
A. 7 s; 30 ft

B. 3.5 s; 366 ft

C. 3.5 s; 618 ft

D. 3.5 s; 226 ft

Question

Anyone please help me on this??   

A catapult launches a boulder with an upward velocity of 112 ft/s. The height of the boulder, h, in feet after t seconds is given by the function h= -16t squared + 112t + 30 . 
How long does it take the boulder to reach its maximum height? What is the boulder’s maximum height? Round to the nearest hundredth, if necessary. 
 A. 7 s; 30 ft  
 
 B. 3.5 s; 366 ft  
 
 C. 3.5 s; 618 ft  
 
 D. 3.5 s; 226 ft

anonymous · Answer

$$-16t^2+112t+30$$ has its maximum at the vertex, which is always at $-\frac{b}{2a}$ in your case it is $-\frac{112}{2\times -16}$

anonymous · Answer

i get $t=\frac{7}{2}=3.5$  to find the maximum height, replace $t$ by 3.5 and see what you get
i would use a calculator

anonymous · Answer

did you understand how i computed the value of $t$ that gave $3.5$?

anonymous · Answer

I understand how you got t

anonymous · Answer

so it's B?