Belinda's mother took the family out to dinner. The food bill came to $72.00. The sales tax is 6% of the cost of food. As a tip, Belinda's mother left 20% of the original food bill. What was her total cost?

To calculate final cost you need to add tax and tip. Because you tip on the food bill without tax, you just add these two.

72 * 0.2 = 14.4 - > tip

72 * 0.06 = 4.32 - > tax

72 + 14.4 + 4.32 = 90.72

So the total cost was $90.72

You can find that faster:

72 * 1.26 = 90.72