Katy wants to buy a pair of inline skates that are on sale for 30% off the original price of $149. the sales tax is 5.75%.

a. calculate the price of the skates if the 30% is taken after the
sales tax is applied.
b. calculate the price of the skates if the 30% is taken before
the sales tax is applied.

This can be a really easy problem if you know what you're doing.

We'll just start by taking the 30% off $149.  That comes to $104.30.

From here, we have all the data we need to answer letters A and B.

a) If sales tax is before after the 30% off, that means that we need to calculate 5.75% and multiply it by $149.  $8.57 is the answer.  But we aren't done just yet.  We need to add $149 and $8.57 together.  That becomes $157.57.  Now we take off that 30% for a grand total of $110.30.

b) If sales tax comes after the 30% off, then we'll take our result from earlier, $104.30, because it is 30% off the original price.  Then we do the %5.75 of our new total, $104.30, and our tax is an extra $6.  Adding this to our total will give us $110.30, the exact same total as before.

Note that I did do a bit of rounding and that the answers are so extremely close that it doesn't really make any difference.  The answers for both a and b are $110.30.  Those are some expensive skates.