There are two answers here: the answer the book wants, and the geek answer.
The answer the book wants is for you to remove the price of the coupon, add the taxes, and divide by 2, because you have 2 pairs of (cheap) shoes.
(68.82 - 3.00 - 5.32)/2
60.5/2
30.25
Now for the geek answer.
The IRS states that all cost reductions apply before taxes, and then taxes applies to the net worth. This is because you add all your items' prices and then tax the whole thing, but the same applies to all your coupons. So, I took the time to calculate the tax value, estimated.
5.32/63.50 = 0.084
About 8(1/2) cents on the dollar.
Now, let's get that pesky coupon out of the way.
60.50
And calculate the actual taxes.
60.50*0.084 = 5.08
Now we'll add it back
60.50 + 5.08 = 65.58
And divide by 2, because we still have two pairs of (cheap) shoes.
65.58/2 =
32.79
Now you understand why the do the coupon first.
Welcome to the IRS.
