Ken's POTW


Change for a Dollar
  1. What is the smallest number of coins that cannot make change for a dollar? Each coin may be selected to be a silver dollar, half dollar, quarter, dime, nickel, or penny. Examples:
    1 coin silver dollar
    2 coins 2 halves
    3 coins half, 2 quarters
    4 coins 4 quarters
    5 coins half, quarter, 2 dimes, nickel
    6 coins 3 quarters, 2 dimes, nickel or half, 5 dimes
    etc.

  2. If all you hold are coins of the above possible denominations, what is the largest amount of money you could have and not be able to make exactly one dollar ($1.00)?

  3. In how many ways can you make change for a dollar using only coins? (For example: four quarters, OR ten dimes, OR nine dimes and two nickels, OR ...)

Source: 1. David Berthold. 2,3. Many sources.


Solution
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