Prime numbers and average value
Source: 2023 Singapore MO Round 2 Junior Q4
July 27, 2023
number theoryprime numbers
Problem Statement
Two distinct 2-digit prime numbers can be written one after the other in 2 different ways to form two 4-digit numbers. For example, 11 and 13 yield 1113 and 1311. If the two 4-digit numbers formed are both divisible by the average value of and , find all possible pairs .