Online PHP editor | refs for ZQHVo

<?php class Ratings { const K = 32; private $rating1; private $rating2; public function __construct($rating1, $rating2) { $this->rating1 = $rating1; $this->rating2 = $rating2; } public function calculateChange() { return round(1 / (1 + pow(10, ($this->rating2 - $this->rating1) / 400)) * 100); } } echo (new Ratings(500, 20))->calculateChange() . "%";