The package probsoln.sty is designed for lecturers who have to generate new problem sheets for their students on a regular basis (e.g. yearly) by randomly selecting a specified number of problems defined in another file. This means that you can easily generate a new problem sheet that is different from the previous year, thus alieviating the temptation of students to seek out the previous year's students and checking out their answers. The solutions to the problems can be defined along with the problem, making it easy to generate the solution sheet from the same source code. The author is Nicola Talbot.