# HIGH SCHOOL – PROBLEMS

## Problem 1

In five years, Tom will be twice as old as Cindy. Thirteen years ago, Tom was three times as old as Cindy. How many years ago was Tom four times as old as Cindy?

## Problem 2

Find the least positive integer n such that for every prime number p,  $p^2 +n$ is never prime.

កុំអាលទាន់ដោនឡូតចំលើយ សាកឆ្លើយលេងៗមើល!!!

សំនួរក្បាលដំបូងចឹង មិនពិបាកណាស់ណាទេ 😛