Print a Nairobi receipt.

Goal

Echo 25 units and Nairobi as busiest.

<?php
$rows = [
  ["city" => "Nairobi", "units" => 12, "shillings" => 480],
  ["city" => "Mombasa", "units" => 8, "shillings" => 320],
  ["city" => "Kisumu", "units" => 5, "shillings" => 200],
];
$units = array_sum(array_column($rows, "units"));
$shillings = array_sum(array_column($rows, "shillings"));
$busiest = $rows[0];
foreach ($rows as $row) {
  if ($row["units"] > $busiest["units"]) {
    $busiest = $row;
  }
}
echo "units ", $units, PHP_EOL;
echo "shillings ", $shillings, PHP_EOL;
echo "busiest ", $busiest["city"], PHP_EOL;