spa treatment costs $57.83 and a gift certificate costs $62.00.
Sarah decided to buy two spa treatments and three gift certificates; therefore, her cost will be
[tex]2(57.83)+3(62.00)=301.66[/tex]Since the purchase is over$100, Sarah gets 12% discount; thereofore, her total purchase cost now is
[tex]\frac{100-12}{100}\times301.66[/tex][tex]=265.46[/tex]Hence, Sarah's total cost is $265.46.