<?php

error_reporting(-1);

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


for ($month = 1; $month <= 20; $month ++) {
	
	$creditBalance = ( $creditBalance * $percent ) + $servicePayment - $monthlyPayment;
	$paymentTotal = $paymentTotal + $monthlyPayment;
	echo "{$month} месяц спустя: долг = {$creditBalance} руб, выплачено всего {$paymentTotal} руб. \n";

     
      if ($creditBalance*$percent+$servicePayment < $monthlyPayment) {
		  $monthlyPayment = $creditBalance*$percent+$servicePayment - $monthlyPayment + $monthlyPayment;
		  }
		  
		  if ($creditBalance <= 0) {
		  	break;
		  }
		  }