Allam just finished a great meal at a restaurant in wisconsin. the sales tax in wisconsin is 5 percent, and it is customary to leave a tip of 15 percent for the server. the tip amount is calculated on the price of the meal before the tax is applied. (sales tax is not calculated on tips.)
if allam ordered a $15 meal, how much money will he have to pay with tax and tip?

So we are given that he ordered a $15 meal
now we need to find how much will he have to pay with tax and tip

so first we find the sales tax of the meal
5% * 15 = 3/4 or 0.75
and the tip
15% * 15 = 9/4 or 2.25

we will add that to the meal price to find the total
15 + 2.25 + 0.75 
total is 18
So If Allam ordered a $15 meal, we will have to pay $18 with tax and tip

Hope this helps :)