Email Exchange

Subj:  can you check my math

Cache,
At Macey's toilet paper is $3.98 for 12 rolls. There are 176 squares on each roll.

At Costco, TP is $17.99 for 36 rolls.  There are 425 sheets on each roll.

Which is the better price?

thanks
love ya,
mom

Subj: Re: can you check my math

While we do have the ability to take numbers and manipulate them in the necessary ways to yield the data that we need to reach such a decision, we do so on the basis that all toilet paper is created equal.  By comparing these numbers we are making this assumption, and while it does make our problem simpler, it certainly has the potential to prove our results incorrect, no matter what we do with the numbers.  Quality must be taken into account in such situations as these.  We have no idea, for example, how long each type of toilet paper will last in our house, and therefore how cost effective each would be. In order to determine this, we would be required to perform a rather complicated study.  There are a multitude of variables that affect our use of toilet paper, and all of these would need to be accounted for.  Each member of our family would be responsible to help collect data about our use of toilet paper over an extended time period.  We would have to try samples of both types and carefully record the results.  The longer this experiment goes on, the more accurate our results will be, so I would suggest no less than 3 weeks per type of toilet paper.  This might also prove to be problematic, seeing as our results might not carry over as the seasons change, because each person in our family may use toilet paper at different rates depending on the time of year.  A thorough study would take years to complete, during which we would discover all types of errors and variables that have not yet been considered that would drastically affect the results.  It would be immensely complicated.  Even if we succeeded in obtaining valid results, it would take such a long time that the prices and quality of the toilet paper would be likely to have changed anyway, rendering our results useless.  This is not a good idea.

 Assuming that both types of toilet paper are equally made, (for the dangers of assuming such a thing, see Paragraph 1) Costco offers the better price with .118 ¢/square vs. Macey's .188 ¢/square.  Seven hundreths of a cent may not seem like much of a difference, so a second calculation might be beneficial to put things into perspective.  If you were to spend $100 at each store, Costco would provide 87,047  sheets and Macey's 53,065.  On average, Costco delivers 60% more toilet paper for the same price. 


{LOVE that kid!}

ps.  PLEASE don't tell him I posted this--he doesn't see my job as family historian as a valid role!