5-digits numbers of tickets
Source: III May Olympiad (Olimpiada de Mayo) 1997 L1 P4
September 17, 2022
number theory
Problem Statement
Joaquín and his brother Andrés go to class every day on the bus. Joaquín always pays for the tickets. Each ticket has a -digit number printed on it. One day, Joaquín observes that the numbers on his tickets - his and his brother's - as well as being consecutive, are such that the sum of the ten digits is precisely . Andrés asks him if the sum of the digits of any of the tickets is and, knowing the answer, he can directly say the number of each ticket. What were those numbers?