An acorn falls from the branch of a tree to the ground 25 feet below. the distance, s, that the acorn is from the ground as it falls is represented by the equation s(t) = –16t^2 + 25, where t is the number of seconds. for which interval of time is the acorn moving through the air?

The problem ask to calculate the interval of time on which the acorn is moving through the air were as the distance is calculated as the equation of S(t)= -16t^2 + 25 and the best answer, based on my calculation is 1.25 seconds. I hope you are satisfied with my answer and feel free to ask for more  

Subtracting is the opposite of adding