<PRE><B>Question 1168151</B>
A projectile that is fired vertically into the air with an initial velocity of 120 ft. per second can be modeled by the equation s = 120t  -  16t2. 
How long will it take for a projectile to reach 216 feet?
---
120t - 16t^2 = 216
Solve for t.
2 solutions, ascending and descending.
=========================
Is it possible for the projectile to reach 900 feet?
Max height is the vertex, at t = -b/2a
t = -120/-32 seconds
Sub for t to find max height.
</PRE>