Answer :
T.C = 3c+(0.06+0.20)(3c)-10
3c = cost of 3 meals
3c(0.06 + 0.20) = tax and tip expenses
10 = value of gift certificate
T.C = 3c + 0.26*3c - 10 = 3.78c - 10.
3c = cost of 3 meals
3c(0.06 + 0.20) = tax and tip expenses
10 = value of gift certificate
T.C = 3c + 0.26*3c - 10 = 3.78c - 10.