In each fusion reaction, 411H nucleus are used.Energy released per Nuclei of 11H=426.7MeV∴ Energy released by 2kg hydrogen (EH)=12000×NA×426.7MeV∴ Energy released by 2kg Vranium (EV)=2352000×NA×200MeVSo,EVEH=235×4×20026.7=7.84∴ Approximately close to 7.62