Mable has a penny, a nickel, a dime, and a quarter, and a half-dollar (1, 5, 10, and 25 and 50 cents, respectively).How many different amounts can Mable make using at least one of the coins she has?
C(5,1) = 5 different amts
C(5,2) = 10 different amts
C(5,3) = 10 different amts
C(5,4) = 5 different amts
C(5,5) = 1 amt
So
31 different amts
subsets of {1, 5, 10, 25, 50}
2^5 - 1 ==31 amounts.
