<?php
error_reporting(-1);

$creditSum = 40000;
$payOut = 5000;
$paymentTotal = 0;

function bank($percent, $comission){
	for ($mounth = 0; $mounth <= 20; $mounth++){
		
		if($creditSum*$percent+$comission <= $payOut) {
			$payOut = $creditSum*$percent+$comission;
			$creditSum = $creditSum*$percent+$comission - $payOut;
			$paymentTotal = $paymentTotal + $payOut;
		break;
		}
	
	
		$creditSum = $creditSum*$percent + $comission - $payOut;
		$paymentTotal = $paymentTotal + $payOut;
		
    }

return $paymentTotal;
}

$dengi = bank(1.04, 500);
echo "Всего выплачено {$dengi} ";
?>