The Gift of the Magi

Date: 09/08/2002 at 12:22:36
From: Cassie
Subject: Gift of Magi

What mathematical error can be found in the first paragraph of 
O. Henry's "The Gift of the Magi"?

Date: 09/08/2002 at 21:25:59
From: Doctor Ian
Subject: Re: Gift of Magi

Hi Cassie,

Here is the paragraph:

  One dollar and eighty-seven cents. That was all. And sixty
  cents of it was in pennies. Pennies saved one and two at a 
  time by bulldozing the grocer and the vegetable man and the
  butcher until one's cheeks burned with the silent imputation 
  of parsimony that such close dealing implied. Three times 
  Della counted it. One dollar and eighty-seven cents. And the
  next day would be Christmas.

Now, presumably, the 'error' you're supposed to find is that if you 
take 60 pennies away from $1.87, you're left with $1.27, which is a 
sum you can only get if you have some pennies.

However, the story doesn't say that _only_ 60 cents of it was in 
pennies. For example, suppose she had nothing but pennies. It would 
_still_ be true that 60 cents of it was in pennies.  

And even if you object to this kind of word-squeezing, note that the 
story was written in 1906, and it doesn't say when it takes place.  
The U.S. was minting three-cent coints as late as 1873. So she could 
have had a silver dollar, 9 three-cent pieces, and 60 pennies. That 
would add up to $1.87.  

So maybe the paragraph contains an error... and maybe it doesn't. 

I hope this helps!

- Doctor Ian, The Math Forum
  http://mathforum.org/dr.math/