Real-World Numbers Here's a boiled-down version of a question from Carnegie Mellon's Lifetime Math program: Your boss tells you to find the best deal in cellular-phone service. Economy service is $19.95 a month plus 31 cents per minute of airtime. Silver service is $40.95 a month plus 16 cents per minute of airtime. Gold service is $80.95 a month with free airtime. Define variables. Write equations. Make tables and graphs. Find slopes and points of intersection. For each plan, how much airtime will $100 buy? For what range of airtime is each plan cheapest?

Updated June 14, 1997 by bwwebmaster
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