Battery Energy and Altitude Change

[gates040]

Homework Statement

An electric scooter has a battery capable of supplying 120 Wh of energy. If friction forces and other losses acount for 60.0% of energy usage, what altitude change can a rider achieve when driving in hilly terrain, if the rider and scooter have a combined weight of 890N.

Homework Equations

Not sure...

The Attempt at a Solution

I just don't understand...

 

[gates040]

Any equations or anything that may make it clear to me would be appreciated. I am capable of solving it for myself, so it is not necessary to actually do the problem. Thank you!