How is the total price including sales tax calculated?

a: (purchase price) x (percent sales tax); then added to original amount

b: (purchase price) x (percent sales tax); then subtracted from original amount

c: (purchase price) x (percent sales tax); then divided by the original amount

d: (purchase price) x (percent sales tax); then multiplied by the original amount

a: (purchase price) x (percent sales tax); then added to original amount.

Step-by-step explanation:

The total price including sales tax is always calculated by adding the sales tax to the original price.

Example:

A book costs $100 with a sales tax of 10%.

The price of the book without sales tax is just $100.

We then compute for the sales tax by multiplying the original price to the sales tax percentage.

100 x 10% or 0.1 = $10.

The sales tax will be 10.

Then we add the sales tax with the original price of $100.

$100 + $10 = $110 Total price after sales tax.