Juan must pay 4 bills and goes to an ATM
Source: Chile Finals 2013 L2 p6
October 5, 2022
combinatoricsnumber theory
Problem Statement
Juan must pay bills. He goes to an ATM, but doesn't remember the amount of the bills. Just know that
a) Each account is a multiple of and is at least .
b) The accounts total 2.
What is the least number of times Juan must use the ATM to make sure he can pay the bills with exact change without any excess money? The cashier has banknotes of , , , and . Juan can decide how much money he asks the cashier each time, but you cannot decide how many bills of each type to give to the cashier.