The sell price of a product is based off of profit margins, dunce. You dont understand basic business101. Its really simple; if the cost of a good doubles, so too does the sell price.  Youre halfway there; if theres a 100% tariff of a $15 shoe, then it only becomes a $30 shoe. Now complete the other half and figure out the sell price of a $30 shoe using the same profit margin as the $15 shoe. This isnt that difficult, you just dont want to admit you made a mistake.