Question 753910
The only "missing" part is determining which option is cheaper.<P>
The average course length is 6 weeks.  The number of months depends on what you use for weeks/month.  Accountants use 4.33 (because 52/12=4.33).  6/4.33 = 1.39 months for an average length course.<P>
Rental price = 13.99 * 1.39 = $19.44.  The book costs $73.99.  Would you rent or buy?<P>
You can also determine how many months of rental would equal or exceed the purchase price.<P>
13.99x >= 73.99<P>
x >= 5.29<P>
5.29 * 4.33 = 22.91.  So when x >= 5.29 (22.91 weeks, about 4 times the average course length), rental price equals or exceeds the purchase price.
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