Ky wants to buy 3 shirts which were originally priced $49.96 each the store will discount the price of the third shirt and then apply a 7.1% tax to a total cost of all three shirts including the tax what will be the mean of the cost show your work

D = discount on third shirt
c = total cost
Sales tax of 7.1% equates to 1.071

c = (Cost of 1st Shirt + Cost of 2nd Shirt + Cost of Third Shirt) * Sales Tax
c = (49.96 + 49.96 + (49.96 - d)) * 1.071

Since you didn't specify the discount on the third shirt, this is the best I can do for you. 

The mean of the cost of the shirts would be c/3