Since it includes 11% sales tax, this means that (purchase)+11% of (purchase)=25.00. Since 11% = 0.11 by multiplying it by 1/100, we have 1*purchase+0.11*purchase=1.11*purchase=25.00. Dividing both sides by 1.11, we get around 22.73 as the original purchase. This means that the difference between the purchase price and the total price is the sales tax, which is around 2.27 dollars.
