Marianna buys a snack combo for $2.50 if the sales tax rate is 8% what is the total price of the combo including tax

There are a couple of ways to do this...

(1) 2.50 + 0.08(2.50) = 2.50 + 0.20 = 2.70 <=
or 
(2) 2.50 (1.08) = 2.70 <=

either way, u get the same answer

Do the math. she originally had 50 dollars on her gift card and she had 12 dollars left on her gift card after she finished her shopping spree. if you subtract 50 minus 12 you get thirty eight dollars as your answer. so therefore, ciara spent 38 dollars total o