PHP with Loop Calculation

Can some help, don’t know how to solve this using loop in PHP

$pay = [20, 40 , 89, 300, 190, 15]; <br/>
$Capital = 1000; <br/>

I want the loop to achieve this result

1000-20 = 980 <br/>
980-40 = 940 <br/>
940-89 = 851 <br/>
851-300 = 551 <br/>
551-190 = 361 <br/>
361-15 = 346 <br/>

My code is:

$newbal = $Capital-$pay <br/>
for ($amount=$newbal; $amount>=$Capital; $amount-=$pay) {
    echo “{$amount} ”; <br/>
    $amount++; <br/>
}

My code is giving me this result:

1000-20 = 980 <br/>
1000-40 = 960 <br/>
1000-89 = 911 <br/>
1000-300 = 700 <br/>
1000-190 = 810 <br/>
1000-15 = 985 <br/>

The code below, loops through the $pays array of integers.

each loop calculates the equation of $captial minus one of the integers and repeats, this is calculated and stored as a string in the $lines variable and at the end of each loop we recalculate the $capital and update the new value of $capital based on the previous calculation of capital = capital - pay

<?php
    $pays = [20, 40 , 89, 300, 190, 15];
    $capital = 1000;

    $lines = [];

    foreach($pays as $pay){
        $lines[] = $capital . "-" . $pay . " = " . ($capital - $pay) . "<br/>";
        $capital -= $pay;
    }

    echo implode("\n", $lines);

?>