A baseball player hits aa baseball into the air with an initial vertical velocity of 48 feet per second from a height of 3 feet(Use h=-16t^2+vt+5)

Write an equation that gives the baseball's height as a function of the time(in seconds) after it is hit.
After how many seconds does the baseball reach it's maximum height?
What is the maximum height?

Since the given equation does not fit the conditions, I suspect they want you to use it as a model. In that case,

h = -16t^2 +48t + 3
Max height is at the vertex of the parabola, which, as usual, occurs at
t = -b/2a = 3/2