Answer
$E_{B/nucleon} = 8.48 MeV/nucleon$
Work Step by Step
To calculate the binding energy, we need to know the mass defect first.
$\Delta m = (15 m_H + 16m_n - m_p) $
$\Delta m = (15 \times 1.007 825 0 u) + (16 \times 1.008 664 9 u) - 30.973 761 6 u $
$\Delta m = 0.282 2518 u$
The binding energy is
$E_B = \Delta m c^2$
$E_B = (0.282 2518 u)(931.49 MeV/u) $
$E_B = 262.915 MeV$
Now the binding energy per nucleon is
$E_{B/nucleon} = \frac{E_B}{A} $
$E_{B/nucleon} = \frac{262.915 MeV}{31} $
$E_{B/nucleon} = 8.48 MeV/nucleon$
