The path of a toy rocket fired into the air can be modelled by a parabola. The rocket, after being launched from the ground, reaches a height of 18 m after 6 seconds and the duration of the flight is 15 seconds.
Use algebra to show that the maximum height reached by the toy rocket is 18.75 m.
The answer uses h = kt(t - 15) as the correct equation, could someone explain how to get this?
As it is a parabola shouldn't it be y = ax^2 + bx + c or y = a(x - h)^2 + k instead?