Answer:
One taco costs $3.75.
Explanation:
Let x = cost of taco
You order 2 tacos: 2x
You add a salad: 2x + 2.5
You pay 8% sales tax on 2x + 2.5, so you pay 1.08(2x + 2.5)
You leave a $3 tip, so the total you pay is: 1.08(2x + 2.5) + 3
The total you pay is $13.80
1.08(2x + 2.5) + 3 = 13.80
Subtract 3 from both sides.
1.08(2x + 2.5) = 10.8
Divide both sides by 1.08
2x + 2.5 = 10
Subtract 2.5 from both sides.
2x = 7.5
x = 3.75
One taco costs $3.75.