Warning: A non-numeric value encountered

Question

Recently updated to PHP 7.1 and start getting following error

Warning: A non-numeric value encountered in on line 29

Here is wha

Answer 1

$sub_total_price = 0; 

foreach($booking_list as $key=>$value) {
        $sub_total_price += ($price * $quantity); 
}

echo $sub_total_price;

it's working 100% :)