check the picture below, that one use feet, but is the same thing, in this case is just centimeters.
a)
so the parabola highest point is at the vertex's y-coordinate, which one will that be?

b)
well, when t = 3, you'll just get h = -4(3)² + 60.
and surely you know what that is.
c)
recall that the x-intercepts occur when y = 0, in this case, when h = 0,
