$${F_{sein} = \frac{ga(M/2 + m/3)}{h} \\ = \frac{(9,8\, \mathrm{m/s^2})(7,58\, \mathrm{m})(72/2\, \mathrm{kg} + 45/3\, \mathrm{kg})}{9,3\, \mathrm{m}} \\ = 407\, \mathrm{N} \approx \underline{\underline{410\, \mathrm{N}}}}$$