<?php
 
 
error_reporting(-1);
 
function getBalance($deposit,$percent,$comission,$paidAmount){  /* начальные условия функции*/
	for ($i=0;$i<100;$i++){ /*задаю цикл*/
		$overallPaid=0;/*начальной выплаты нету */
		$deposit = ($deposit*$percent)+$comission-$paidAmount;/*операция с суммой*/
		$overallPaid=$paidAmount+ $overallPaid;/*высчитываю затраты*/
		if ($deposit<0){ /*условие цикла для разрыва*/
			$overallPaid= $overallPaid+ $paidAmount+$deposit;/*высчитываю остаток*/
			return $overallPaid;
			break;
			} 
		}
	}
 
$abc =  getBalance (39999,1.1,1000,5000);
echo "$abc";

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