Dividing Pizza with a Clock

Source: Alok Goyal Puzzle Page ( http://alokgoyal1971.com/ ) . Alok is ex-IIT Delhi, Partner at Helion VC
Problem:
Part I (Easy): Using a clock, divide a pizza among 12 people
Part II (Difficult): Using a clock, divide a pizza among 11 people?
Problem:
Part I (Easy): Using a clock, divide a pizza among 12 people
Part II (Difficult): Using a clock, divide a pizza among 11 people?