Pogo stick question regarding potential and kinetic energy.?

a childs pogo stick stores energy in a spring with spring constant 21800 N/M. at position A(x1=-.06m) the spring compression is a maximum and the child is momentarily at rest. at position B ( x=0 m) the spring is relaxed and the child is moving upward. at position C (x2= height) the spring is still relaxed and the child is again momentarly at rest at the top of the jump. the acceleration of gravity is 9.8 m/s^2. m of child and spring = 29 kg. at position C determine the height ?at position B calculate the speed of the child at x=0 ? determine the magnitude of x for which the kinetic energy of the system is at a max ?