The total price in dollars that would go in box B is $8.58
Here we want to calculate the value of the sales tax and the price including tax
From the question, we are told that the sales tax rate is 7.25%
So the sales tax for a pillow of $8 will be;
7.25% of $8
The sales tax value is $0.58
The price including tax will be the price before tax plus the sales tax
Mathematically, that will be $8 + $0.58 = $8.58