Answer
1064 feet
Work Step by Step
We are given that the height of a projectile at any time t can be described by the polynomial function $P(t)=-16t^{2}+300t$.
In order to find the height at $t=20$ seconds, we can calculate the value of $P(20)$.
$P(20)=-16(14^{2})+300(14)=-16(196)+4200=-3136+4200=1064$ feet
