Total price = $266.63 + $317.29+62.78=646.7
Discount = 15%
Discount amount = (15/100) x 646.7
=$97.005
Price after discount = $646.7 - $97.005
=$549.695
Sales tax = 6%
Sales tax amount =(6/100) x $549.695
=$32.9817
Total cost = Price after discount + sales tax amount
=$549.695 + $32.9817
=$582.6767
=$582.68