Sharp EL-9900 - Manual (Page 60)

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Chapter 4
Basic Graphing Features
— Basic Keyboard
This chapter takes the knowledge you have gained in Chapter 3 several steps further.
Note: To try the examples in this chapter, it is required that the Basic Keyboard is
already set up by the user. To learn how to set up the Basic Keyboard, read
“Changing the Keyboard” in Chapter 1.
1. Try it!
Two math expressions can be derived from the above fare
systems. If “y” represents the cost, while “x” represents the
mileage, then:
y = 2 + 1.8x .................... Tomato Cab’s fare system
y = 3.5 + 1.2x ................ Orange Cab’s fare system
Use the calculator’s graphing capabilities to figure out the
approximate point where the Orange Cab gets ahead of the
Tomato Cab, in terms of cost performance.
There are two taxi cab companies in your city, Tomato Cab and Orange Cab,
with different fare systems. The Tomato Cab charges $2.00 upon entering the
taxi cab, and $1.80 for each mile the taxi travels. The Orange Cab, on the other
hand, charges $3.50 plus $1.20 per mile. This means that taking the Tomato
Cab will initially cost less than
going with the Orange Cab, but
will be more expensive as you
travel longer distances.
Suppose you need to go to a place
3 miles away from where you are
now. Which cab company should
you take to save money?