The most common method for determining project progress and, ultimately, project success is called Earned Value Analysis. The attached PowerPoint presentation explains this quite well using an example to help you understand it. Then complete the exercise attached. It asks you to determine the earned value of a few projects at certain points in their progress. One of the most tried and true methods of approaching this questions is to first draw a diagram of where the project was planned to be at this particular point in time. That will help you determine what was planned so that you can then check for variance against what actually happened.