Finding the lowest point for a bungee jumper with spring constant

[~Sam~]

Homework Statement

79kg person jumps from a platform that is 100m above the water. He is attached by a bungee chord with sprint constant 40 N/m and length 35 m. Now he jumps off. How far is he above the water now when the chord has reached maximum elongation

Homework Equations

F=ma, Ek= 1/2mv² Ep=mgh...etc

The Attempt at a Solution

I'm kind of stuck.. I know it involves energy, but the maximum elongation of the chord confuses me.

 

[Pengwuino]

All that it means is that the person is no longer falling and is just about to begin moving upward. In other words, the bunjee jumpers gravitational potential energy has been fully converted into the spring potential energy.