Answer :
assuming that each kind of seat is unnique and different from each other
( assume 4 kinds, premium, gold, silver, bronze, or premium, not premium, not premium, not premium)
so fraciton is parts out of whole so
1 out of 4 toal parts is 1/4
( assume 4 kinds, premium, gold, silver, bronze, or premium, not premium, not premium, not premium)
so fraciton is parts out of whole so
1 out of 4 toal parts is 1/4