MathDB
The Mientka Publishing Company

Source:

January 18, 2009
linear algebramatrix

Problem Statement

Mientka Publishing Company prices its bestseller Where's Walter? as follows: C(n) \equal{} \begin{cases} 12n, &\text{if } 1 \le n \le 24\\ 11n, &\text{if } 25 \le n \le 48\\ 10n, &\text{if } 49 \le n \end{cases} where n n is the number of books ordered, and C(n) C(n) is the cost in dollars of n n books. Notice that 25 25 books cost less than 24 24 books. For how many values of n n is it cheaper to buy more than n n books than to buy exactly n n books?
<spanclass=latexbold>(A)</span> 3<spanclass=latexbold>(B)</span> 4<spanclass=latexbold>(C)</span> 5<spanclass=latexbold>(D)</span> 6<spanclass=latexbold>(E)</span> 8 <span class='latex-bold'>(A)</span>\ 3\qquad <span class='latex-bold'>(B)</span>\ 4\qquad <span class='latex-bold'>(C)</span>\ 5\qquad <span class='latex-bold'>(D)</span>\ 6\qquad <span class='latex-bold'>(E)</span>\ 8