private ICollection<IProblem> GenerateProblemList()
        {
            ICollection<IProblem> problems = new List<IProblem>();

            IProblemFactory problemFactory = new ProblemFactory();

            for (int i = 0; i < NumberOfProblemsInExam; i++)
            {
                problems.Add(problemFactory.CreateProblem());
            }

            return problems;
        }
        private ICollection <IProblem> GenerateProblemList()
        {
            ICollection <IProblem> problems = new List <IProblem>();

            IProblemFactory problemFactory = new ProblemFactory();

            for (int i = 0; i < NumberOfProblemsInExam; i++)
            {
                problems.Add(problemFactory.CreateProblem());
            }

            return(problems);
        }