Recall the following fact given in class Fact Let S be a finite set with S n Then P S 22 Let S 1 2 3 4 5 6 7 8 9 a How many subsets does S have in total b How many subsets A of S satisfy the property that 2 3 4 5 6 7 8 9 A G Cak Hint It s easy to list all such subsets