Conservation of energy

A 75 kg bungee jumper steps off a platform 50 m above a river. By the time he reaches the lowest point, 5.0 m above the water, he is momentarily at rest. Assuming air resistance does $1.0 \times 10^4\,\text{J}$ of work on him during the fall, what is the elastic potential energy stored in the stretched cord at the lowest point? Take $g = 9.81\,\text{m s}^{-2}$.