<?php

    $price = 10;
    $tax = 20;
    echo "<Br />(Before)Price: \t$price and Tax: \t$tax";

    function calcSalesTax(&$price, &$tax){
        $price = 40;
        $tax = 60;
        $total = $price + ($price * $tax);
        echo "<Br />(Function Call) Price: \t$price and Tax: \t$tax";
        echo "<Br />Total cost: \t$total";
    }

    calcSalesTax($price, $tax);
    echo "<Br />(After) Price: \t$price and Tax: \t$tax";

?>