<?php 
$balance = 10000;
$percent = 0.1;
$age = 16;
for (;;) { /*while(true)*/
  $balance = $balance + $balance* $percent;
  $age++;
  if($balance >= 1000000){
    $balance = round($balance);
    echo "На балансе {$balance} рублей, Анону {$age} лет";
    break;
  }
}