In Try This 4 you may have determined the original function 
The function that described Claire’s trip was 
, and the function that described Ahmed’s trip was 
. The functions for Claire’s and Ahmed’s trips could be graphed to help you see how much less time it would take for Ahmed to complete his trip compared to the time it would take for Claire to complete her trip.
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Deciding between texting and talk plans for cellphones can be confusing. Read “Example 5” on page 439 of the textbook. Notice how the rational functions are determined for each texting plan to help you compare the average cost per text. Part of the solution is to graph the functions representing the texting plans; note how these graphs give a nice visual representation of the problem.
Add the term rational function to your copy of Glossary Terms.