<?php

$creditBalance = 40000; /* стартовый баланс */
$percent = 1.03; /* процент банка */
$comission = 1000;
$payment = 5000;
$paymentTotal = 0;

for ($mnts = 1; $mnts <= 24; $mnts++) {
	$creditBalance = ($creditBalance * $percent) + $comission -$payment;
	$paymentTotal = $paymentTotal + $payment;
	echo "{$mnts} месяц спустя долг = {$creditBalance} руб, всего выплачено {$paymentTotal} руб.\n";
	if ($creditBalance < 0) {
		echo "Хватит платить!";
		break;
	}
}