<?php

$creditBalance = 40000;
$percent = 1.03;
$servicePayment = 1000;
$monthlyPayment = 5000;
$paymentTotal = 0;

for ($month = 1; $month <= 20; $month++) {
	$creditBalance = ($creditBalance * $percent) + $servicePayment - $monthlyPayment;
	if ($creditBalance < 5000) {
		$monthlyPayment = $creditBalance;
		$paymentTotal = ($paymentTotal + $monthlyPayment);
		echo "{$month} месяц спустя: долг = {$creditBalance} руб, выплачено всего {$paymentTotal} руб.\n";
		echo "с меня хватит!\n";
		break;
	} elseif ($creditBalance > 5000) {
	$paymentTotal = ($paymentTotal + $monthlyPayment);
	echo "{$month} месяц спустя: долг = {$creditBalance} руб, выплачено всего {$paymentTotal} руб.\n";
	}  
}