ok well if you have a cost of $12 per box then you would multiply that by 15 to get the total cost of all the boxes before tax.
12*15=180
So the total cost of all the boxes before tax is $180.
Then to find the tax you multiply the total cost of all the boxes before tax which is $180 by 6%.
180*0.06=10.8 then you have to add the tax number to total cost to find out how much you pay with tax.
so you pay $169.2 for all the boxes of citrus fruits