<p>Hi guys,</p>
<p>Blue Book, Practice Test #5, Math Section #13.</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÷x)1K, 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>(A) 40
(B) 50
(C) 60
(D) 590
(E) 600</p>
<p>Please help me</p>
<p>dont understand what you mean by x#100, but this is a simple problem where you substitute 20 for x and 640 for C(x). When doing that, the answer does not come out, so I would assume that you typed out the question wrong. Upon looking at the question in the book, it is:
c(x) = (600x-200)/x +k and the correct answer would be 50, or B. </p>
<p>Like the person above said, just plug in the 20 for x and 640 for c(x). And solve for K. K comes out to be 50 which is B.</p>
<p>Wow, that is easy. I know how to do that. My book must be a missprint. The number sign/hashtag sign is clearly written in the book. There are also some other problems that are misprinted. I was wondering, “■■■ is this.” lol.</p>
<p>Thanks!</p>
<p>Yes, there is a mistake with this question. This was corrected in the errata that was issued by the Collegeboard. Here is the link: [Official</a> SAT Guide Errata](<a href=“http://us.macmillan.com/splash/bookseller/documents/2009/09b_640_SAT_SG_Errata_WEB_090728.pdf"]Official”>http://us.macmillan.com/splash/bookseller/documents/2009/09b_640_SAT_SG_Errata_WEB_090728.pdf)</p>