In order to determine the costs of the computer, first calculate the 30% of the original price of the computer, just as follow:
(30/100)(500.00) = 150.00
then, with the 30% of discount the price is:
500.00 - 150.00 = 350.00
next, for people arrived by 9am there is an additional 10% off, then, you have:
(10/100)(350.00) = 35.00
and the final price of the computer is:
350.00 - 35.00 = 315.00
The final price is $315.00
