martin finds a shirt on sale for 10% off at a department store. The original price was $20 . martin must also pay 8.5% sales tax. how can you determine the total cost of an item including tax if you know the price of the items and the tax rate?

In this problem it decreased 20%

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)