51ab, a1b9 4-digit numbers wanted
Source: XIII May Olympiad (Olimpiada de Mayo) 2007 L1 P2
September 22, 2022
number theoryDigits
Problem Statement
Let and be two positive integers where and are digits. is known to be multiple of a positive two-digit number and is the next multiple of that number . Find the number and the digits and . Justify why there are no other possibilities.