rnz.php

<?php
/**
 * Screw you John Campbell! I couldn't work it out either!
 */
for ($found = false, $a = 20, $b = 60; $found === false; $a++, $b++) {
    if ($a + 20 === $b - 20 && ($a - 22) * 2 === $b) {
        $found = true;
        echo "$a + 20 = " . ($a+20) . " and $b - 20 = " . ($b-20), PHP_EOL;
        echo "$a - 22 = " . ($a-22) . " which doubled is the same as $b", PHP_EOL;
        break;
    }
}