The number of ATP molecules utilized for the fixation of 6 molecules of ${\mathrm{CO}}_2$ in Rice and Maize is respectively

For the fixation of 6${\mathrm{CO}}_2$ to form a molecule of hexose or glucose ${\mathrm{C}}_3$ plants like Rice utilize 18 ATP in Calvin cycle and ${\mathrm{C}}_4$plants like maize utilize 30 ATP.