Help with a chapter 5 further mechanics question?

I'm struggling with a further mechanics question where a particle of mass m is released and falls under gravity before hitting an inclined plane of 30 degrees. The coefficient of restitution between the ball and the plane is e, and the ratio of the K.E. before and after impact is 12:7.
Would someone be able to do a worked solution to help me out?

If you post the question (pic) and some form of attempt/sketch, I can give you a few hints.