In the USA, there are coins of 1 cent, 5 cents, 10 cents, 25 cents, 50 cents and 1 dollar.
You can pay one dollar using either one coin (100), or two coins (50 + 50), or three (50 + 25 + 25), or four (25 + 25 + 25 + 25), etc.

What is the smallest number such that you cannot pay $1 with that many coins?

(In reply to i think i have the answer by sherwin)

Are you trying to be a Penny?

You have shown one combination of 9 coins that doesn't add up to $1. But 4 nickels, 3 dimes, and 2 quarters add up to 4x5+3x10+2x50=100 cents=$1. Hence 9 is not the smallest number such that you cannot pay $1 with that many coins.

Posted by Richard on 2004-07-19 22:39:23