Olympiad Maths Prep

Track / Stage 3 / 248 of 260 #248 of 2000

Problem 248

AMC 10/12, early questions
Number theory Difficulty 4.0 Find the answer South African Mathematics Olympiad · South Africa

The smallest number bigger than 20152015 that is divisible by all of 22, 33, 44, 55 and 66 is

Official solution

20402040

In order to be divisible by 22, 33, 44, 55 and 66, the number only needs to be divisible by 22×3×52^2 \times 3 \times 5, i.e. it must be a multiple of 6060. The smallest multiple of 6060 bigger than 20152015 is 20402040.

Source: MathNet, licensed CC-BY-4.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.