Solution :-
given that,
→ Cost of meal before tax = $ 40
and,
→ Tax = 8.5%
So,
→ Total tax paid = 8.5% of cost of meal = (40 * 8.5)/100 = $ 3.4
now,
→ Tip = 18% of cost of meal = (18 * 40)/100 = $ 7.2
then,
→ Total cost of the meal = Cost of meal before tax + Total tax paid + Tip = 40 + 3.4 + 7.2 = $50.6 ≈ $51 (Ans.)
Shortcut :-
→ Total cost of the meal = Cost of meal * (100% + 8.5% tax + 18% tip) = 40(1 + 0.085 + 0.18) = 40 * 1.265 = $50.6 ≈ $51 (Ans.)