The Miller family's total bill was $67.50, if they want to give the waitress a 20% tip based on total bill, how much money will they need to leave the waitress? (tip money only)

The Miller family's total bill was $67.50, if they want to give the waitress a 20% tip based on the total bill, how much money will they need to leave the waitress? (tip money only)

$87.50
$81.00
$54.00
$13.50