26. The flight of a projectile is modeled by the function d = -5t2 + 18t + 8, where d represents distance above the ground measured in meters, and t represents time of flight measured in seconds. According to this model, the projectile will hit the ground when t = ?

Answer and Explanation

Your Answer is

Correct Answer is H

Explanation

Knock the ground when d=0, so -5t2+18t+8=0, then (5t+2)(t-4)=0, because t>0, so t=4, so choose H.