1. A television director is scheduling a certain sponsor's commercials for an upcoming broadcast. There are six slots available for commercials. In how many ways may the director schedule the commercials:

(10 marks)

1. if the sponsor has six different commercials, each to be shown once?
2. if the sponsor has three different commercials, each to be shown twice?
3. if the sponsor has two different commercials, each to be shown three times?
4. if the sponsor has three different commercials, the first of which is to be shown three times, the second two times, and the third once?