So the towel costs 15$. After tax, you have to pay 16.25$. This means that tax is 1.25$. To see what percent the tax is, you have to compare the fraction of 15/1.25, to the fraction of 100/x. We can cross multiply to get 125=15x. We divide both sides by 15 to get 125/15=x. This is 25/3=x, or 8.333=x. So the answer is 8.33333%, or 8 and 1/3%