<?php

error_reporting(-1);
mb_internal_encoding('utf-8');

function credit($percent, $comission, $pay, $monthlyPayment, $balance)	{
	$balance = $balance*$percent+$pay;
	$month=0;
	$paymentTotal=0;
		for($i=0; $i<=42; $i++)	{
			$month++;
			$paymentTotal=$paymentTotal+$monthlyPayment;
			$balance=$balance+$comission-$monthlyPayment;
				if(($balance+$comission)<=$monthlyPayment)	{
					$paymentTotal=$paymentTotal+$balance+$comission;
					$month++;
					echo "$month месяцев потребовалось на выплату долга.\n";
					break;
				}
		}
	return $paymentTotal;
}

$HomoCredit = credit(1.04, 500, 0, 5000, 40000);
$Softbank = credit(1.03, 1000, 0, 5000, 40000);
$StrawberryBank = credit(1.02, 0, 7777, 5000, 40000);

echo "HomoCredit:{$HomoCredit}руб.\n";
echo "Softbank:{$Softbank}руб.\n";
echo "StrawberryBank:{$StrawberryBank}руб.\n";