Buying a cat and getting the correct change...
Source: ToT 2003 SO-3
June 26, 2011
combinatorics unsolvedcombinatorics
Problem Statement
A salesman and a customer altogether have rubles in coins and bills of rubles. The customer has enough money to buy a Cat in the Bag which costs the integer number of rubles. Prove that the customer can buy the Cat and get the correct change.