Question

You order two tacos and a salad. The salad costs $2.50. You pay 8% sales tax and leave a $3 tip. You pay a total of $13.80. How much does one taco cost? Let t represent the cost of one taco.

Answer 1

Let T = cost of a taco
Let S = cost of a salad

(2 tacos + 1 salad) + (8 % of 2 tacos and 1 salad) + 3 = 13.80

2T + S + .08(2T + S) + 3 = 13.80
2T + 2.5 + .08(2T + 2.5) + 3 = 13.80
2T + 2.5 + .16T + .20 + 3 = 13.80
2.16T + 5.7 = 13.80
2.16T = 8.10
T = 8.10/2.16 = $3.75

Check: 2T + S + .08(2T + S) + 3 = 13.80
2(3.75) + 2.50 + .08(2(3.75)+2.5) + 3 = 13.80
7.5 + 2.5 + .08(10) + 3 = 13.8
13.80 = 13.80
Answer checks as correct