# Sales Tax equation

After a $6\%$ sales tax, a shirt cost $\$15.37$. Find the original cost of the shirt before sales tax. Exactly how do I approach this? Thanks - If this is homework, tag it as homework. If it is, then you need to ask your teacher to help you out before you ask strangers to do it for you. If it is not homework, then where are you coming across these problems, and why are you trying to answer them? PS This is not "linear algebra". – Arturo Magidin Oct 4 '10 at 1:47 Both of the questions you posted tonight look very much like hw off of the same assignment. This site is not meant to be an online homework solver. There are other resources available for that =P If you are not in this position please tell us what the motivation for these problems are, what you have tried thus far, and where you are getting stuck or what it is you feel that you are not understanding clearly. – jericson Oct 4 '10 at 1:54 ## 3 Answers Let x equal the original cost of the shirt. Then x plus the sales tax (.06 of x) equals 15.37. Solve for x. - US\$15.37 is 106% of the original cost. So solve for the cost.

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15.37 = 1.06x


Where x is the original cost of the t-shirt. The 6% sales tax would make the t-shirt cost 106% of the original price, so now just do some simple algebra to isolate x.

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Welcome to Math Stack Exchange number11. Here is a link explaining how we prefer HW questions to be handled on this site and why –  jericson Oct 4 '10 at 2:38
How much info should I give? Obviously, the answer shouldn't be there now, but is the 15.37/1.06 acceptable? –  DMan Oct 4 '10 at 2:40
I think setting up the equation for him like you did in the first line is plenty of a push in the right direction. Especially since this isn't the first question the user has asked like this today. As a general rule, the more effort the asker puts into solving the problem and asking the question, the more hints they should be given. Hope that helps. Also feel free to search our meta for other guidelines pertaining to this site. Thanks! –  jericson Oct 4 '10 at 3:00
Edited, thanks for the tips. –  DMan Oct 4 '10 at 3:02