Is this a typo or an unusual question?

Test Preparation SAT Preparation
1

<p>I really don't even know where to begin on this question:</p>

<p>The total daily cost c, in dollars, of producing x units of a certain product is given by the function
c(x) 5 600x -200 1k,
................x
where k is a constant and x # 100. If 20 units were produced yesterday for a total cost of $640, what is the value of k?</p>

<p>(dots before x in order to provide spacing)</p>

<p>Thanks.</p>

2

<p>looks solvable but just the style of the question makes me doubt its authenticity. Probably just a typo.</p>

3

<p>That actually was a typo in the new BB, but the problem is still solvable.</p>

4

<p>I’m not sure as to what it’s supposed to be.</p>

5

<p>It should be c(x) = …</p>

<p>Here’s a PDF of all the typos in the new BB, it includes the one you’re talking about.
<a href=“http://images.barnesandnoble.com/pimages/resources/PDF/09b_640_SAT_SG_Errata_WEB_090728.pdf[/url]”>http://images.barnesandnoble.com/pimages/resources/PDF/09b_640_SAT_SG_Errata_WEB_090728.pdf&lt;/a&gt;&lt;/p&gt;

6

<p>Ah, I see. Thank you.</p>